A Brief History of American Armor

The United States military has had a long, if at times strained, relationship with the armored vehicle. Mechanization of American armed forces has not always followed a smooth path, but its origins predate even the internal combustion engine. Development persisted, and today the armored vehicle is a ubiquitous component of the nation's ground forces.

Contents
1. In the Beginning: Trails Blazed
2. The Great War: The Tank Corps
3. Between the Wars: Stagnation
4. World War II: Obscurity to Maturity
5. The Atomic Age: Retaining Relevance
6. Vietnam to Desert Storm: The Struggle for Modernization
7. Post-Cold War: Focusing Anew
8. In Summary

In the Beginning: Trails Blazed

As far back as the American Civil War, trains were used to quickly and easily move men and supplies across large distances. Battle-ready troops were carried for reconnaissance, patrolling, raiding, or escort duties, and soldiers occasionally dismounted from trains directly into action. Artillery pieces were soon mounted to give the trains a greater punch and the artillery greater mobility. After Confederate attacks on Union trains, a Federal engine was proofed against small arms fire with iron plating as early as April 1861. Though this initially occurred on a local level, more organized arming and armoring programs quickly followed on both sides, drawing inspiration from ironclad naval vessels. These armored railway monitors, again armed with artillery pieces and featuring loopholes from which mounted infantry could fire their rifles, acted as rolling fortresses to provide protection to railway repair workers, point installations, and supply trains, and also to perform offensive missions. One Union design placed a naval gun on top of an armored boxcar in the vein of waterborne monitors, adumbrating later fighting vehicle layouts by giving the ordnance a free field of fire. More thinly-armored rifle cars filled with troops accompanied the railway monitors to provide infantry support either by dismounting or by firing through ports in the cars' walls.McGrath, 33. Zumbro, The Iron Cavalry, 72-3. Gabel, Railroad Generalship, 5-6, 8, 14-7, 20. Gabel, Rails to Oblivion, 9, 11. Koenig, 37-9, 52-3, 98-101, 104-19, 145-8, 156, 160, 190-8, 209-10, 217, 230-4.

The first three automobiles purchased by the US military were electric examples built by the Woods Motor Vehicle Company of Chicago,Crismon, Modern U.S. Military Vehicles, 6. but the invention of the internal combustion engine truly freed the fighting vehicle from the confines of the rails. As early as 1896, flamboyant inventor E.J. Pennington had drawn up a design for a roofless armored car sporting two machine guns.Duncan, 1-2. At the turn of the century, Major Royal P. Davidson of the Illinois National Guard and Charles Duryea of Massachusetts's Duryea Motor Wagon Company constructed a self-propelled tricycle armed with a Colt Model 1895 machine gun; Davidson later armed a four-wheeled Duryea with a Colt machine gun and 125 rounds of ammunition. Experiments run with these and similar machine gun-armed cars were such a success that in 1903 Commanding General of the US Army Lieutenant General Nelson A. Miles recommended to Secretary of War Elihu Root--without success--that five cavalry regiments adopt cars instead of horses. Davidson switched to Cadillac automobiles by 1910 and used these as the basis for armored and semi-armored radio, reconnaissance, ambulance, balloon destroyer, kitchen, and supply vehicles. Two years later a searchlight was added to the machine gun mount to enable a modicum of night fighting capability as well as signaling. A convoy of Davidson's cars successfully trekked from Chicago to San Francisco in 1915 to see how the machines would fare cross-country on the nation's roads.Davidson eventually reached the rank of colonel. Ogorkiewicz, Armoured Forces, 188, 423-4. Hunnicutt, Armored Car, 9-10. Crismon, U.S. Military Wheeled Vehicles, 6. Crabtree, 8. Kutz, 34-6. Icks, U.S. Armored Cars, 169-71.

Armored car Number 1

Concurrently with Davidson's expedition, the American southwest saw active use of military vehicles. A handful of armored cars patrolled the country's southern border, and Brigadier General John J. Pershing's forces were accompanied on their 1916 punitive expedition into Mexico by hundreds of trucks and a smaller number of tracked tractors. An infantry company was mounted in trucks, while the tracked vehicles, manufactured by the Holt Tractor Company of California, were used as cargo carriers, or more specifically cargo pullers as they towed supply-laden skids. Pershing was a frequent sight in a Dodge passenger car, sometimes using it as a mobile command post.Hunnicutt, Armored Car, 13-4. House, 14. Crismon, U.S. Military Wheeled Vehicles, 6. Crismon, U.S. Military Tracked Vehicles, 7. Hofmann, Through Mobility We Conquer, 45-7. Blumenson, The Patton Papers 1885-1940, I: 354. D'Este, 169. In early 1925, Holt merged with the C.L. Best Tractor Company to form the Caterpillar Tractor Company. See Caterpillar, <https://www.caterpillar.com/en/company/history/1920.html>. It was also in this unlikely locale that the first motorized assault by American forces took place: Cavalry Second Lieutenant George S. Patton, Jr., commanding fourteen men mounted in three Dodge cars trying to procure corn to feed horses, diverted from this mission to search two nearby ranches for Julio Cárdenas, commander of los Dorados, bodyguards of Pancho Villa. Patton and his men used their cars to position themselves around the ranches and assaulted directly from the automobiles. Cárdenas was found at the second ranch and, along with two other Villistas, was killed in a firefight in which Patton's men suffered no losses.Blumenson, The Patton Papers 1885-1940, I: 359-66. D'Este, 172-5. Wilson, 14. Robert H. Patton, 152-5. Yeide, Fighting Patton, 6-11. Mikolashek, 8-10.

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The Great War: The Tank Corps

Tanks, of course, debuted in the First World War, and American machines played a large role in their invention. Indigenous tracked vehicles were uncommon in Europe before World War I, and American designs had been imported to several countries for agricultural and transport work. After trials in October 1912 and May 1914 showed Holt tractors' prowess over soft terrain, Austria-Hungary arranged for local production, but the shipment of supplies from the US was subsequently impeded by the war.Ludvigsen, 27. Glanfield, 14-5. Some completed tractors were imported to Austria before the war, however. See Markus Pöhlmann, "Images of War, Armament and Mechanization in Imperial Germany, 1880-1914," in Genesis, Employment, Aftermath, Searle, ed., 27. Great Britain used upwards of sixteen hundred Holt Model 75 tractors as artillery prime movers during the conflict, and these machines helped familiarize the British military with tracklaying vehicles. Lieutenant Colonel Ernest Swinton, one of the men Great Britain credited with the tank's invention, took inspiration for his idea from the description in a friend's letter of a Holt tracked tractor.Ogorkiewicz, Tanks, 23-4. Glanfield, 15-6, 20-1. Swinton, 12-3, 57-8, 60, 77, 111-4, 116, 138-9. For discussion of the Royal Commission on Awards to Inventors, which awarded Swinton £1000 for his role in the tank's invention, see Fletcher, The British Tanks 1915-19, 187-90. France and Britain experimented independently on their early tank designs, and Holt tractors took part in trials in both countries. The Holts were joined in British tests by machines built by the Bullock Creeping Grip Tractor Company of Chicago and Wisconsin's Killen-Strait Manufacturing Company; indeed, the upturned track profile of the Killen-Strait machine may have influenced the rhomboid shape of production British tanks, and a Killen-Strait may have become the first armored tracked vehicle in history when a Delaunay-Belleville armored car body was experimentally mounted on it. More concretely, the running gear of the French Schneider CA and Saint-Chamond tanks as well as that of Germany's A7V were based on Holt's design, with Holt even receiving patent royalties from the Germans.Gale, 24. Ventham and Fletcher, 16. Ogorkiewicz, Tanks, 25-6, 28-9, 33-6, 47-8. Vauvillier, 17-8, 20. Olivier Lahaie, "The Development of French Tank Warfare on the Western Front, 1916-1918," in Genesis, Employment, Aftermath, 60, 65, 68. Fletcher, Landships, 4, 7-11. Fletcher, The British Tanks 1915-19, 25, 32-3. Liddell Hart, The Tanks, 1: 28, 33-5, 40-1. Smithers, A New Excalibur, 11, 31-5, 37. Perrett, 35-6. Glanfield, 26-31, 34, 84-5, 87-8, 95-6, 101-2, 105-6, 109, 118, 128-9. Stern, 21-2, 24, 29-30, 103. J.P. Harris, 17-8, 26, 28-9. Christy Campbell, 58-9, 74-6, 80-1, 95-6, 301-2. Duncan, 16. Ławrynowicz, 9-10, 12-6, 22, 27-8, 36. Morozov, 41-9. Hundleby and Strasheim, 16-7. Ludvigsen, 88, 164. Ralf Raths, "From the Bremerwagen to the A7V: German Tank Production and Armoured Warfare, 1916-1918," in Genesis, Employment, Aftermath, 87.

America's delayed entry into World War I gave the country a late start on its own technical and tactical tank development. In June 1917 Major General Pershing, now commanding the American Expeditionary Force (AEF), read reports by American observers of British and French tank actions, and he subsequently created committees to study the new form of warfare.Wilson, 9. Hunnicutt, Stuart, 9. Hofmann, Through Mobility We Conquer, 50-5. During a 25 August 1917 meeting between two of these observers and members of the British Tank Corps, US Army Major Frank Parker and Tank Corps G.S.O.1 Lieutenant-Colonel J.F.C. Fuller discussed a paper Parker had written on tank tactics. Though Parker's ideas on combined arms using aviation, tanks, motorized artillery, and motorized infantry were not adopted by his own country during the war, Fuller was impressed since they meshed well with concepts he had himself been expressing.Fuller, Tanks in the Great War, 552-6, recounts a paper written by "Lieutenant-Colonel H. Parker," while in Memoirs, 157-8, Fuller does not recall the American officer by name. Hofmann, Through Mobility We Conquer, 58-9, provides positive identification.

Captain Patton meanwhile was performing a rear-area assignment supervising Pershing's headquarters, but by late September 1917 was itching for a more active role. He considered taking command of an infantry battalion, but when offered a position to help create a tank force for the US Army, he concluded this endeavor would be both more interesting and more beneficial to his career. On 10 November 1917 Patton was ordered to the AEF schools at Langres in northeastern France to set up a program for training American soldiers in the use of the French Renault FT light tank. Indeed Patton was the first man assigned to the American tank service, and First Lieutenant Elgin Braine was detailed to be his assistant. Patton and his entourage observed Allied training and manufacturing methods and set about applying the lessons learned. Their efforts included meeting with tank experts such as the commander of the French Artillerie spéciale, Général J.E. Estienne, and British Tank Corps commander Brigadier-General Hugh Elles, chief engineer Lieutenant-Colonel Frank Searle, and Fuller. The Americans also suggested four modifications to the FT which were subsequently fielded, namely mounting a self-starter, a voice tube for the crew, a gun mount that could allow interchange between the machine gun and the 37mm gun, and installing a bulkhead separating the crew from the engine.Wilson, 15. D'Este, 196, 198, 200-1, 203-8, 213, 854. Cameron, Mobility, Shock, and Firepower, 3. Blumenson, The Patton Papers 1885-1940, I: 468-73, 478-83, 501-2, 508. Mikolashek, 13-4, 22-5, 34. British rhomboid heavy tanks were predicted to be useful as well, and an American annex to the British Tank School at Wareham was formed.Wilson, 51. The AEF then requested from the War Department five heavy and twenty light tank battalions comprised of 375 British rhomboids and 1,500 French FTs, along with two heavy and five light tank training battalions that were to be kept in the United States.Rockenbach, 11-2. Wilson, 36. Johnson, Fast Tanks and Heavy Bombers, 31. Fuller, Tanks in the Great War, 556. Yeide, Fighting Patton, 13.

The US Army formalized its Tank Corps on 26 January 1918, and Cavalry Colonel Samuel D. Rockenbach was assigned to command the unit.Jones, Rarey, and Icks, 107. "Armored Force, Command, and Center," 1. Hofmann, Through Mobility We Conquer, 59. Patton was appointed commander of the light tank training school that he set up near Bourg, and also of the US 1st Tank Brigade upon its formation.Wilson, 15, 96. Hunnicutt, Stuart, 6. Mikolashek, 24, 46-7, 63-4. By May 1918 it was intended to enlarge the Tank Corps to fifteen tank brigades, each composed of one heavy and two light tank battalions, but only three American tank battalions would see combat: the 41st Heavy Tank Battalion, and the 1st Tank Brigade which was composed of the 326th and 327th Light Tank Battalions. Confusingly, starting on 8 June the units were redesignated to bring them into congruence with the numbering scheme assigned to the National Army, with the 41st becoming the 301st Tank Battalion, the 1st Tank Brigade the 304th Tank Brigade, and its battalions the 344th and 345th, respectively. More battalions and brigades were in the process of being formed and trained, and some would actually reach the front, but the war ended before they could enter the fray: the 304th Tank Brigade was relieved in the line by the 306th (formerly 3d) Tank Brigade on 9 November 1918, but the latter unit saw no action before the Armistice was signed.Fuller, Tanks in the Great War, 556-63. See MAJ Sereno Brett, "Operations Report of the 1st (304th) Tank Brigade from Noon September 26th, 1918 to November 10, 1918," in Rockenbach, 123; Wilson, 44, 181. Kaplan, ed., 1. Lemons, Organization and Markings of United States Armored Units 1918-1941, 8-9.

Organizationally, the light tank battalions were each composed of a headquarters company and three tank companies; each tank company of a headquarters with a signals tank and nine fighting tanks, and three five-tank platoons each with two 37mm gun tanks and three machine gun tanks. Sounding like a formidable force itself, the company headquarters was intended to dole out spare tanks to its line companies to make up for breakdowns caused by the machines' mechanical fragility. The heavy tank battalion was organized to British specifications during the war, with three companies of sixteen tanks each, the companies each having four four-tank sections. A pending table of organization for the heavy tank battalion saw a signals tank in the battalion headquarters, and three tank companies of three five-tank platoons and a company headquarters with a signals tank and eight spare machines.Lemons, Organization and Markings of United States Armored Units 1918-1941, 9-11, 17-8, 25.

The Tank Corps provided effective infantry support once it was loosed upon the enemy, but one small action provided the prescient with a tantalizing view into the future. West of the town of Woël on 14 September 1918, during the St. Mihiel offensive that saw the combat debut of American tanks, the 326th Light Tank Battalion had been unable to link with infantry units of the 1st Division. Patton and battalion commander Major Sereno Brett sent a patrol of three FTs and five soldiers two kilometers past Woël to St. Benoit. On its return leg the patrol, headed by Second Lieutenant Edwin McClure, was ambushed by a battalion of infantry, at least eight machine guns, and a battery of 77mm field guns. Five tanks under the leadership of Second Lieutenant Gordon Grant were dispatched to help, and the group of eight machines managed to rout the enemy force six kilometers back to the town of Jonville, capturing four 77mm guns and knocking out over twelve machine guns at the cost of six wounded and no tanks lost. This engagement showed that even these mechanically frail and short-ranged tanks were capable of missions independent of the infantry to which they had been bound, and it had a deep effect on the thinking of the brigade commander.Two tanks broke down, but were able to be towed back to friendly lines. The 77mm guns were ultimately disabled and abandoned when artillery fire interrupted the process of hitching them to the tanks, causing all six of the American casualties. COL G.S. Patton, Jr., "OPERATIONS of the 304th Tank Brigade, September 12th to 15th, 1918," in Rockenbach, 87-9. Wilson, 115-8. Mikolashek, 71, 74-5. Yeide, Fighting Patton, 28-9. In contrast to Wilson and Mikolashek, the patrol leader's name is consistently spelled "McCluer" in Kaplan, ed.

The eyes of American artillerists were also opened to the benefits of mechanization during the war. A handful of heavy ordnances were mounted on tracked tractors during St. Mihiel, and although the mobility of these vehicles was too poor for them to have much of an effect on the battle, a burgeoning horse shortage prompted the War Department to decree in September 1918 that all 155mm howitzers and one 75mm gun regiment in each division would be towed by tractors instead of horses. The fighting ended before more than eleven 155mm regiments could be changed over, but nonetheless in December 1918 Chief of Field Artillery Major General William J. Snow wanted research conducted to determine if all Army artillery could become tractor-drawn.Dastrup, King of Battle, 174-5.

Manufacturing tanks in the United States proved problematic for the militaries of Britain, France, and America herself. The British Army's Lieutenant George Field had traveled to the American midwest in mid-1915 to evaluate the tank-building ability of tractor manufacturers. He successfully negotiated production arrangements with Bullock, Killen-Strait, and Milwaukee's Federal Bridge Company and Waukeshau Engine Company, but this work was for naught when the Landships Committee of the British Army demurred in favor of domestic production.Glanfield, 87, 95, 110. In July 1917 Estienne had floated the idea of constructing the FT in America to help the strapped French manufacturing base, and in that September proposals were made to build French light and British heavy tanks in the US to equip its own Tank Corps. Due in part to bureaucratic hurdles, though, these schemes made little headway, and American tankers fought in European-produced FTs and Mark V and Mark V* heavy tanks for the whole of the war, while small numbers of French Saint-Chamonds were used for driver training. Indeed, due to their own dearth of machines, and in exchange for the heavy tanks and training provided, the British demanded that the American heavy tank units be used solely with the British Expeditionary Force. American production of a copy of the FT was finally negotiated after much work had been expended by Braine. This resulted in the 6-ton tank M1917, but the first of these did not appear until October 1918, and only 64 were completed by the end of the war. Despite their tardiness, Patton rated them better than the French machines.Gale, 116-7. Lemons, Organization and Markings of United States Armored Units 1918-1941, 8. Hofmann, Through Mobility We Conquer, 57. Wilson, 56, 79-86, 222. Hunnicutt, Stuart, 17. Blumenson, The Patton Papers 1885-1940, II: 710. Ławrynowicz, 44. Braine recounts many hurdles he encountered in a report reproduced in Kaplan, ed., 52-63.

A new rhomboidal heavy tank, the Mark VIII, was intended to be manufactured in France using American automotive assemblies and British armor and armament. The Liberty V-12 aircraft engine was earmarked for use by December 1917, and possessed impressive advantages over the Ricardo six-cylinder engine powering the latest British heavy tanks, including producing more than twice the horsepower at a weight savings of over 1,800lb (820kg). However, the Liberty was needed to fill airplane orders for Britain and France as well as the United States, and none were released to the Ordnance Department for tanks until June 1918 when the entire Liberty engine production run of the Trego Motors Corporation of New Haven, Connecticut, was assigned for this purpose since that company's product quality was insufficient for aerial use. The lack of engines combined with shortages of British supplies and incompletion of the assembly factory in Neuvy-Pailloux to prevent any Mk. VIIIs from being manufactured in time to see action.Wilson, 77-9. Johnson, Fast Tanks and Heavy Bombers, 32. Childs, 47. J.P. Harris, 136. Broman, 38. Glanfield, 250-2. Neal, 186-91, 221-4. Stern reproduces the Anglo-American treaty on Mk. VIII tank production on pp.198-201.

Heavy tank Mark VIII

With the cessation of hostilities, the original contracts for 4,440 M1917s were cancelled after 950 had been built, and the US constructed one hundred Mark VIIIs to its own specifications at Rock Island Arsenal in Illinois once the manufacturing coalition decomposed after the Armistice. Production of the Ford 3-ton M1918, which was planned to eclipse fifteen thousand machines, stopped at fifteen due to the end of the war and the Tank Corps's dissatisfaction with the design after testing in France.Hunnicutt, Stuart, 14, 17. Lemons, The Six Ton Special Tractor Model 1917, 3. Wilson, 85-6, 222. Hunnicutt, Firepower, 11. Childs, 47. Crismon, U.S. Military Tracked Vehicles, 51. Hofmann, Through Mobility We Conquer, 63. Ogorkiewicz, Tanks, 53-4. Cameron, Armor in Battle, 3. The M1918s were nonetheless dispersed to units, and on 18 November 1918 one was deployed from Camp Polk in Raleigh, North Carolina, to help quell a race riot in nearby Winston-Salem, although calm had returned by the time it arrived on the scene.Lemons, Organization and Markings of United States Armored Units 1918-1941, 9-11. Ponton, E-mail to the author. North Carolina Collection, <https://northcarolinaroom.wordpress.com/2013/11/12/the-great-1918-race-riot-part-2/>. Clarey, <https://triad-city-beat.com/last-lynch-mob-winston-salems-1918-race-riot-first-draft-history/2/>. The Winston-Salem Journal, "Alleged Mob Leaders Arrested and Jailed; Others May Be Caught."

3-ton special tractor M1918

These were not the only production plans that became casualties of the Armistice. In mid-1917 the British Army began using obsolete heavy tanks as supply carriers with their armament reduced to a single machine gun or nothing at all; a few months later, supply sledges began to be towed by these supply tanks as well as by current tanks making their way to the front line. Compared to supply trains consisting of pack animals and foot troops, mechanized transport offered significant economical benefits, superior cross-country performance, and a manpower savings of over 97%. Thus, the British decided to purchase ten thousand American tractors to take over supply transport duties in the planned 1919 offensive, but the fighting ended before more than a handful had been accepted.Fuller, Tanks in the Great War, 323, 405. Fletcher, Landships, 25. Martel, In the Wake of the Tank, 53-5. Watson, 225, 233, 239, 241, 243-256. The sledges, however, were poorly engineered with tow cables that tended to snap. See Watson, 239. Coming full circle then, Britain's successful use of supply tanks inspired the order of a large number of American tractors, while similar machines had earlier inspired the tank's very invention and had also taken part in its experimental development.

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Between the Wars: Stagnation

The end of World War I meant a drastic culling of the world's armed forces, and the US armored forces were no exception. At the time of the Armistice, the US Tank Corps consisted of 1,235 officers and 18,977 other ranks, but in March 1919 its authorization was reduced to 300 officers and 5,000 enlisted men. Four months later Congress declared that the Tank Corps would be limited to no more than 154 officers and 2,508 other ranks.Wilson, 219, 222. Cameron, Mobility, Shock, and Firepower, 9. Cameron, Armor in Battle, 3-4. D'Este, 300.

More distressing than the manpower cuts was the drive to end the independence of the tankers. Legislators were eager to keep the costs of a peacetime army to a minimum, and mechanized forces were expensive; proposals were afoot to roll the armor into the Infantry branch. Some Tank Corps officers--including both Patton, who had visions of tanks acting as horse cavalry even as he first applied to join the tanks in late 1917, and Lieutenant Colonel Dwight D. Eisenhower, who was commanding the tank training center at Camp Colt, Pennsylvania--penned articles and lectures asserting that the tank had a future outside of infantry support and that the Tank Corps should be kept as a separate branch of the Army. But the weighty and contrary opinions of both the AEF Superior Board on Organization and Tactics and of Pershing helped give impetus to those in favor of the tanks' subsumption. The Superior Board was formed after the war to digest lessons learned, and it opined that tanks were not able to perform independent missions and should be used as infantry accompaniment and support. Pershing, promoted in September 1919 to the unprecedented rank of General of the Armies of the United States, agreed with the Superior Board's conclusion: later that year, during Congressional hearings on Army reorganization, he testified in favor of making the tanks a supporting arm of the Infantry. In addition, despite being in favor of fast tanks that could execute raids in the enemy's rear areas, Rockenbach failed to articulate a role for tanks beyond that of infantry support. Consequently the National Defense Act of 1920, passed on 2 June, did away with the Tank Corps and assigned all tanks and their units to the Infantry. Officially, tanks were simply to help the infantry advance, with medium tanks following a rolling artillery barrage and seeking out hostile antitank guns while light tanks accompanied the riflemen and destroyed enemy machine guns or strongpoints. Officers like Patton and Eisenhower faced threats of career sabotage or even courts-martial if they persisted in espousing views contrary to this doctrine. The Act established custodial branch chiefs for Infantry, Field Artillery, Cavalry, Coast Artillery, and for the new Air Service and Chemical Warfare Service branches, but armor was relegated to a dependent role.Johnson, Fast Tanks and Heavy Bombers, 39, 72. Mikolashek, 107-8. Wilson, 223. Robert H. Patton, 175. Nye, 51-2. Gabel, The U.S. Army GHQ Maneuvers of 1941, 22. Jarymowycz, 24-6. Cameron, Mobility, Shock, and Firepower, 14. Cameron, Armor in Battle, 4-5. Hofmann, Through Mobility We Conquer, 77, 86-7, 88-9. Blumenson, The Patton Papers 1885-1940, II: 783. D'Este, 297-300. Jordan, 14-5. Odom, 17, 55-8, 201-2. Rockenbach, while still in command of the Infantry's tanks, did later advocate adding tanks to Cavalry divisions. See Cameron, Mobility, Shock, and Firepower, 29, and Hofmann, Through Mobility We Conquer, 85.

Subordination to the Infantry stifled tank design and doctrinal development, and tankers' morale and staffing also suffered. Patton, who had been mulling a return to the Cavalry since February 1918 thanks in part to its better career-advancement prospects, was pushed into action with the Tanks Corps's absorption and rejoined his former branch in September 1920.Wilson, 227. Cameron, Mobility, Shock, and Firepower, 22. Blumenson, The Patton Papers 1885-1940, II: 525, 709, 805-7. D'Este, 276. Mikolashek, 58-9, 105-7. Rockenbach, promoted to brigadier general in June 1918, became a colonel once more after the Act's passage. See Wilson, 226-7. Likewise, Colonel Patton reverted to a captain, although he was promoted to major the next day. Blumenson, The Patton Papers 1885-1940, II: 804. D'Este, 278, 300-302. Farago, 68, 98, 102-3. Another side effect of the Act was the division of the Infantry's doctrinal and organizational responsibilities from the design and production of tanks, which was controlled by the Ordnance Department. The offices of the branch chiefs created by the Act also formed additional stops through which procurement paperwork had to pass. This decentralization and increased bureaucracy, combined with the users' and designers' sometimes competing desires--and even competing opinions of multiple potential users of the same equipment or vehicle--would have repercussions in the next war and beyond.Johnson, Fast Tanks and Heavy Bombers, 59. Green, Thomson, and Roots, 194-5. Blumenson, The Patton Papers 1885-1940, II: 790-1. The Army had already been impacted by this situation in the preceding decades, and the struggle would continue even after World War II. See Calhoun, 40-3, 47-8, 190, 281, 287-9; Hofmann, Through Mobility We Conquer, 186; Adams, 62; Herbert, 27-8; Odom, 206-11; and Sorely, ed., Press On!, II: 1272-3.

Once the Act was effected, infantry divisions were each given a company of tanks; the Tank School at Camp Meade, Maryland, retained the 17th Heavy and 16th Light Tank Battalions; and the Infantry School at Fort Benning, Georgia, obtained the 15th Composite Tank Battalion for training.Cameron, Mobility, Shock, and Firepower, 21. Wilson, 231. Ogorkiewicz, Tanks, 80. Lemons, Organization and Markings of United States Armored Units 1918-1941, 29. Thirteen National Guard companies were formed. The Act formed a Provisional Tank Brigade out of a number of these, but this unit never even met as a whole since the individual companies were meted out to different infantry divisions for support duties. This geographical situation was eased in 1937 when the infantry tanks were brought to Fort Benning and organized into six infantry support battalions.Salecker, 5-6. S.D. Badsey, "The American Experience of Armour 1919-53," in Armoured Warfare, Harris and Toase, eds., 129. Lemons, Organization and Markings of United States Armored Units 1918-1941, 29. The light tank organization remained the same as that practiced during the war, but by 1925 the heavy tank battalion was composed of three companies made of three three-tank platoons and a headquarters section with six spare tanks.Lemons, Organization and Markings of United States Armored Units 1918-1941, 30, 32.

Nevertheless the potential of the armored vehicle could not be ignored. The formation of the country's first Experimental Mechanized Force (EMF) was approved at the end of 1927, and it took to the field from 1 July to 20 September 1928. Inspired by Secretary of War Dwight F. Davis's viewing of a similar British formation, this unit was to test the ability of mobile mechanized units to be self-sufficient. The EMF consisted of an armored car troop; a company of tanks; a machine gun company; a self-propelled artillery battery; an engineer company; a company of Ordnance troops; quartermaster, signal, and chemical warfare troops; and a headquarters company.Hofmann, Through Mobility We Conquer, 107. Timothy K. Nenninger, "Organizational Milestones in the Development of American Armor, 1920-1940," in Camp Colt to Desert Storm, Hofmann and Starry, eds., 40. "Armored Force, Command, and Center," 1-2. Cameron, Mobility, Shock, and Firepower, 32, 41. Cameron, Armor in Battle, 5. Morton, 18. Gillie, 20. The EMF had a small number of new M1 light tanks made by Cunningham out of Rochester, New York, but was forced to retain worn-out M1917s due to the niggardly defense spending policies of the interwar years. By this point, some knowledgeable officers contended that the M1917s would actually be hazardous to their crews should they be needed in battle.Cameron, Mobility, Shock, and Firepower, 133. Hofmann, Through Mobility We Conquer, 107.

Light tank M1

A Mechanization Board was formed in May 1928 and recommended that a permanent mechanized force be formed. Approved by Army Chief of Staff General Charles Summerall, this Mechanized Force, commanded by Cavalry Colonel Daniel Van Voorhis, appeared at Fort Eustis, Virginia, in 1930 and consisted of an armored car troop; a portee field artillery battery; a tank company; an antiaircraft detachment; a machine gun company; a company each of ordnance troops and engineers; chemical warfare and motor repair troops; and a headquarters company. The Mechanized Force rolled over thin ice, however, both legal and traditional. There were fears of it eventually trying to break away like the Army Air Service. Unlike the Mechanized Force, though, the Air Service had been established by the National Defense Act of 1920, and the creation of another Army branch would require similar legislative action. Its experimentation combined the Infantry's control of tanks with what were typically cavalry actions, and the latter branch did not suffer this encroachment lightly. Simultaneously with the formation and deployment of the Mechanized Force, in April 1930 Infantry Tank School commandant Colonel James Parsons crafted a plan for establishing a tank division for each of the six field armies. Missions for these formations would have included traditionally cavalry jobs, and there was a complete lack of horse cavalry in the proposal. The scheme was rebutted by Chief of Cavalry Major General Guy Henry via Major Patton--balancing his confidence in mechanization by publicly toeing the horse-friendly Cavalry line--and was ultimately denied by the Secretary of War.Hofmann, Through Mobility We Conquer, 124-6. Yeide, Fighting Patton, 46. David E. Johnson, "From Frontier Constabulatory to Modern Army: The U.S. Army between the World Wars," in The Challenge of Change, Winton and Mets, eds., 190. Blumenson, The Patton Papers 1885-1940, II: 953. Cameron, Armor in Battle, 6. Army Chief of Staff General Douglas MacArthur soon eliminated the Mechanized Force as a separate entity in 1931, succumbing to the combination of pressure from within the Army and monetary concerns dictated by the Great Depression, and ordered instead that all combat branches should modernize themselves as much as possible.Hofmann, Through Mobility We Conquer, 106, 108-9, 127-36, 146-48, 153. Grow, "Part 1," 24, 28. Gillie, 34-5, 43. Green, Thomson, and Roots, 192. Jarymowycz, 29. "Armored Force, Command, and Center," 2-3. Cameron, Mobility, Shock, and Firepower, 45-8. Cameron, Armor in Battle, 6-7. House, 102. Morton, 26-8. Blumenson, The Patton Papers 1885-1940, II: 962-6. Nye, 87. Odom, 103-4.

After its dissolution, the remnants of the Mechanized Force were assigned to the Cavalry and redesignated the Detachment for Mechanized Cavalry Regiment, taking up station at Camp Knox in western Kentucky in late 1931. Renamed Fort Knox the following year, thus began the base's almost 80-year association with Army armored forces, lasting until 2010 when Fort Benning became the home of armor due to the base realignment and closure program. The Detachment for Mechanized Cavalry Regiment became part of the 1st Cavalry Regiment, with the formation then being renamed the 1st Cavalry Regiment (Mechanized). Van Voorhis remained in command, and Lieutenant Colonel Adna Chaffee was the unit's executive officer. It was intended to assign the 1st Cavalry Regiment (Mechanized) to the new 7th Cavalry Brigade (Mechanized) in 1932, but this brigade was not created until early 1933 and it took even longer to transfer in the troopers assigned to it.Cameron, Mobility, Shock, and Firepower, 49-50. Cameron, Armor in Battle, 7-8. Gillie, 47-50. Grow, "Part 2," 25-33. Hofmann, Through Mobility We Conquer, 157-60, 163, 170-1. Once formed, the brigade performed experiments and exercises to test equipment and formations throughout the mid-late 1930s, and its progressive-minded members fought to advance the cause of using mechanized forces to perform traditional cavalry missions as well as deeper maneuvers. Due to the fact that tanks were still technically under control of the Infantry according to the 1920 National Defense Act, tanks developed for the Cavalry were forced to undergo a change of nomenclature and became "combat cars."Gillie, 43-4; Nenninger, 46-7. The French employed similar mental gymnastics with their Automitrailleuses de Combat: See Ogorkiewicz, Armoured Forces, 64-5.

Combat car M1

MacArthur hoped that component development would improve under the policy of each branch modernizing itself. Because of the limited potential for profits during the interwar period, though, few private concerns entered the field of armored vehicle design. One notable exception was an enterprising and eccentric automobile engineer named J. Walter Christie. Christie had been creating self-propelled artillery mounts since 1916, and incorporated into many of his machines was the ability to move on tracks as normal or on road wheels only. Wheeled movement was usually powered by either chains or gearing connecting the drive wheels to the rear road wheels. This feature enabled the vehicles to travel at high speeds over roads on their wheels, while also giving them good cross-country mobility once the tracks were installed. Christie's early designs were unsprung or suspended by coil springs, but his M1928 tank debuted a suspension concept that would become famously synonymous with his name: large road wheels would be individually sprung on leading or trailing arms using tall and relatively soft helical springs that were housed inside a double-walled hull. This provided the wheels greater vertical movement than the previous bogie suspensions, allowing very high speeds when combined with the soft springs.

Unfortunately for Christie, there were issues that soured the Army's reaction to his machines. Christie already had a long history with the Ordnance Department, having been awarded $995,000 in contracts from 1916 through 1924 yet producing no vehicles that were accepted.Neal, 236-7. Christie's prototype tanks had a reputation for shoddy workmanship and unreliability, and he continually refused to build his vehicles to the contract specifications laid out by the Army, often making modifications unilaterally. The quality of Christie's machines was so dismal that in 1932 Cavalry Major Robert W. Grow noted about the Christie tanks being used by the Detachment for Mechanized Cavalry/Detachment, 1st Cavalry (Mechanized): "On only one day were all four Christies running...I complained bitterly that the Christie was not built as a fighting vehicle but only as a mobile 'cradle for an engine.'"Hunnicutt, Sherman, 22-3. George F. Hofmann, "Army Doctrine and the Christie Tank: Failing to Exploit the Operational Level of War," in Camp Colt to Desert Storm, 110-1, 113-4. Hofmann, Through Mobility We Conquer, 117-8, 138-44, 163-5, 180, 242-3. Johnson, Fast Tanks and Heavy Bombers, 118-9. Crismon, U.S. Military Tracked Vehicles, 87. Cameron, Mobility, Shock, and Firepower, 129. Zaloga, Armored Thunderbolt, 11-2. Grow, "Part 2," 29. Grow would reach the rank of major general and would later command the 6th Armored Division in combat.

Another factor that did little to endear Christie to the US War Department was his dealings with foreign countries, which occurred clandestinely due to his own government's strictures on exporting war materiel. Important figures in the Red Army, for example mechanization proponent and eventual marshal of the Soviet Union Mikhail N. Tukhachevskiy, were aware of and respected Christie's work. Indeed, two of his tanks were shipped to the Soviet Union in December 1930 before the US Army had taken delivery of any. Soviet tanks developed from these two machines would include the BT series and T-34, both of which would play major roles for the Red Army.Milsom, 41, alleges that Tukhachevskiy, executed in 1937 during the purges, even proposed to Iosif V. Stalin that the USSR should offer Christie a large salary in exchange for assistance in designing Soviet tanks, but this proposal was not acted upon. Simpkin in Deep Battle reproduces an article written by Tukhachevskiy in 1931-2 where Tukhachevskiy mentions Christie by name in regards to the latter's work on flying tanks, and also asserts that tanks with "combined wheeled and tracked running gear" are superior to those just using tracks. See pp.140, 142. Zaloga, Armored Thunderbolt, 11-2. Hofmann, Through Mobility We Conquer, 136-8. Cameron, Mobility, Shock, and Firepower, 129-30. Hofmann, "Army Doctrine and the Christie Tank," 111, 130. Zheltov and Makarov, 18-20. Knight, A13 Mk.I & Mk.II Cruiser Tanks, 8. Milsom, 96. Fleischer, 18. Bean and Fowler, 19, 68. Habeck, 115, 150-2. Baryatinskiy, Light Tanks, 5, 36. Kavalerchik, 100-4. Gudmundsson, 48-9. Potapov, <http://english.battlefield.ru/index.php?option=com_content&view=article&id=1:christie​&catid=8&Itemid=102&tmpl=component&print=1&layout=default&page=>. In 1930 Poland contracted a machine, but their order was accepted by the US government when the Poles defaulted on the transaction due to Christie subsequently requiring their purchase of a $90,000 production license prior to delivery, contrary to the original contract stipulations. Nonetheless, work was being conducted on a Christie-suspended tank in Poland when the Germans invaded eight years later.Knight, A13 Mk.I & Mk.II Cruiser Tanks, 7-8. Neal, 239-40. Ogorkiewicz, Armoured Forces, 266-7, says Poland was to receive two machines from Christie. Poland's intention to obtain Christie's machine may have influenced the Soviet Union's purchase. See Kavalerchik, 101. The Japanese embarked on an army modernization effort in 1925, and Christie twice tried to entice their representatives. The chronic unreliability of his machines, however, helped to finally dissuade interest in 1932.Hara, 1, 3. A British delegation observing Soviet maneuvers in 1936 was impressed enough with the fast BTs that the United Kingdom purchased a tank from Christie after paying off a lien on the vehicle. Subsequently many of Britain's cruiser tanks incorporated Christie's suspension, and the well-sloped bow of Christie's machine inspired the front hull of the A12 Matilda infantry tank.Knight, A13 Mk.I & Mk.II Cruiser Tanks, 4-11, 18-9, 20-1. Fletcher, Mechanised Force, 120-3. Hofmann, Through Mobility We Conquer, 144, 219-21. Hofmann, "Army Doctrine and the Christie Tank," 116. J.P. Harris, 277-8. Liddell Hart, The Tanks, 1: 373-4. Martel, An Outspoken Soldier, 127-8, 137, 140. On the Matilda's bow, see Fletcher, British Battle Tanks, 11. There is apparently some dispute as to the exact designation of the tanks Christie sold to the UK and USSR. Hofmann claims that the British received the M1930 or M1931, while Fletcher says it was an M1931 or even a US Army prototype version of the M1931, called the convertible medium tank T3. Forczyk is in the M1931 camp, and Fleischer and Milsom say the Soviets imported two "M.1931(T-3)"s and "M-1931 (T-3)"s, respectively. Bean and Fowler agree that they were T3s, but Habeck mentions the T1E1, Potapov says the USSR bought two M1930s, and Baryatinskiy calls them M.1940s, with Zheltov and Makarov agreeing that they were "Model 1940" but referred to in the USSR as simply "Christie." The "1940" designation may be because that, as Bean and Fowler assert, Christie so labeled the tanks himself to reflect how advanced he thought the design was. Hofmann, Through Mobility We Conquer, 117, alleges that it was Cavalry Major C.C. Benson who took to calling Christie's tank the "Model 1940" for the same reason. Knight proposes that the "M1940" designation came from Christie, and the UK received an M1932 which may have been the M1940 originally built for Poland or a T3E1 that had been released from US Army service. He notes, "The ultimate provenance of the tank supplied to the United Kingdom as the 'M1932' is not definitively possible to ascertain." Christie then traveled to Vincennes in 1938 to stage an exhibition for the French. Though France declined to purchase any examples, the demonstration and later exposure to British cruisers did have some influence. Joseph Molinié, an engineer at the Ateliers de Construction d'Issy-les-Moulineaux, made use of the suspension in a design called the AMX 40, but this had not even reached the prototype stage by the time Germany attacked in May 1940.Vauvillier, 118. Fletcher, British Battle Tanks, 51. After World War II, Molinié advanced to being an Ingenieur-Général and worked on tank projects including the AMX-13 and headed the AMX-30 program. See Robinson and Seignon, 16.

On the other hand, despite enthusiasm from officers including Patton, Christie's suspension was not destined to play a large role in American tank history.Christie was a frequent visitor to Patton's house, where work on models of his vehicles took place. Robert H. Patton, 238; Sobel, 14. Patton may have gone so far as to help finance Christie's company. See Farago, 100; D'Este, 296; and Essame, 20. Patton's son, however, disagrees. See Hofmann, Through Mobility We Conquer, 115-6, 164. The US Army never did wholly buy into the wheel-track conversion theory, but did go so far as to standardize and accept a handful of the Rock Island Arsenal-designed convertible medium tank M1, which used Christie's suspension. A few combat car prototypes were constructed along these lines, since Christie's dream of high-speed tanks was more suited to the Cavalry's mobile mission, however none of these vehicles were standardized. The early prototypes of the 76mm gun motor carriage (GMC) M18 also used Christie's suspension, but this was dropped in favor of torsion bars which took up less room inside the hull.Hofmann, "Army Doctrine and the Christie Tank," 130. Hofmann, Through Mobility We Conquer, 282. Hunnicutt, Stuart, 307. Dunham, 26, 61. Gill, 38. Interestingly, even on the eve of the German invasion, some powerful forces in the Red Army also wanted the T-34 switched to torsion bars, or even its production halted entirely in favor of the T-34M design which used torsion bars instead of Christie springs, yielding 20% more room in the fighting compartment. See Baryatinskiy, T-34 Medium Tank, 18-20; Michulec and Zientarzewski, 145; Kavalerchik, 128-9; and Forczyk, 110. In the end, the Army concluded that Christie's designs, even those classed as medium tanks, did not provide an appreciable offensive benefit over existing light tanks despite being twice as expensive as contemporary vehicles.Hunnicutt, Stuart, 66. Hunnicutt, Sherman, 24. In the parsimonious environment of the interwar years, this finding was damning.

Convertible medium tank M1

Another automotive engineer was more successful at having his designs adopted by the United States. Harry A. Knox, formerly of both the eponymous Knox Automobile Company and Knox Motor Truck Company, gained employment by the Ordnance Department in the early 1920s. He filed dozens of patents related to mechanization, including for complete vehicles, and granted them to the government for royalty-free manufacturing and use. One important invention bearing his name was volute spring suspension. Armored vehicles using vertical or horizontal volute spring suspension dominated American motor pools in the 1930s and 1940s, and included the light tanks M2, M3, M5, M22, and various nonstandardized Marmon-Herrington designs; Cavalry combat cars M1 and M2; medium tanks M2, M3, M4, and M7; the heavy tank M6; half-track cars M2 and M9A1; half-track personnel carriers M3 and M5; and all variants thereof. While not having the amplitude of independent suspensions such as Christie's and also being prone to tire failure due to overheating, the external volute spring bogies took up no interior room and were typically less intensive to repair or replace.LaChance, <https://www.hemmings.com/magazine/hcc/2007/01/Old-Porcupine---Knox/1394619.html>. "From the Editor: The Forgotten Legacy of Harry Knox," <https://tankandafvnews.com/2015/01/29/from-the-editor-the-forgotten-legacy-of-harry-knox/#more-57>. US GAO, <http://www.gao.gov/10/fl0046486.php>. Pasholok, <http://tankarchives.blogspot.com/2017/04/light-tanks-t1e4-and-t2e1-experiments.html>. Brockman et al., 16, 25. Loza, Commanding the Red Army's Sherman Tanks, 50-2. The T-34 could also be prone to shedding overheated tires: see Bryukhov, 72-3, 75-6.

Light tank M5A1 Stuart

A second significant innovation Knox oversaw was tracks with rubber bushings around the track pins. Though causing an increase in rolling resistance and being potentially more prone to being thrown, the bushings reduced the force necessary to wrench the track around the drive sprocket, made the track more flexible when responding to steering actions or shock forces, and decreased wear between the track pins and pin holes. When paired with rubber shoes, these tracks proved very durable, especially on road surfaces. Quantitatively, during World War II enemy dry-pin tracks lasted approximately 600 miles (970km), and even by the end of the war the Soviet Union had trouble making tracks that withstood 1,000km (620 miles). On the other hand, many US tracks could see 3,000 miles (4,800km)."From the Editor: The Forgotten Legacy of Harry Knox," <https://tankandafvnews.com/2015/01/29/from-the-editor-the-forgotten-legacy-of-harry-knox/#more-57>. Pasholok, <http://tankarchives.blogspot.com/2017/04/light-tanks-t1e4-and-t2e1-experiments.html>. Ogorkiewicz, Technology of Tanks, 228. Wong, Theory of Ground Vehicles, 321-2. Wong, Terramechanics and Off-road Vehicle Engineering, 132. Cameron, Mobility, Shock, and Firepower, 390. Research, Investigation and Experimentation in the Field of Amphibian Vehicles, 180, 191, 197. Kavalerchik, 184. Green, Thomson, and Roots, 309. Dr. Ferdinand Porsche would also be a fan of volute spring suspensions, utilizing them in his Type 245 study of 1943 as well as on the Maus heavy tank. See Ludvigsen, 200, 220; and Spielberger and Doyle, Special Panzer Variants, 50, 54, 63-4, 147. Rubber-shoed and -bushed track was such a revelation that one British tanker commented upon his first viewing of a Lend-Lease light tank M3: "There had never been anything like [the tracks] in the British Army. Each track link was mounted in solid rubber blocks on which the vehicle moved. After one look we wondered why the hell British tank designers had never thought of it."Quoted from Crisp, 17. Indeed, "live" rubber-bushed track remains the predominant type in use today.

In contrast to suspensions and tracks, engines to power new tanks became a source of trouble that would resonate into World War II. Tank engines required a large amount of power to be developed from as small a physical space as practical, so that the amount of armor enclosing the engine--and consequently the vehicle's weight--could be kept to a minimum. Private engine manufacturers between the wars had been under no such size and power obligations, and the Army had little money to give for tank engine development in the 1920s and 1930s.Green, Thomson, and Roots, 287-90. For example the prototype medium tanks M1921 and M1922, delivered to Aberdeen Proving Grounds for testing in February 1922 and March 1923, respectively, were similar designs except for differing suspensions. Each was powered by a 6-cylinder speedboat engine from Murray and Tregurtha of Boston. Nominally rated for 220 horsepower at 1,200rpm, during testing only 195 horsepower was managed. It was thus weak for the 41,000-50,000lb (18,500-23,000kg) mass of the vehicles, and also turned out to be unreliable in this terrestrial application. After a survey of potential marketed replacement engines revealed no better candidates, the Ordnance Department in February 1924 contracted the Packard Motor Car Company of Detroit to design and build a single bespoke tank engine for $33,000. Packard called this new V-8 the 1T-1330, and had it ready by June 1925. This engine solved the reliability issue, being used with little issue in both the M1921 and the briefly-standardized medium tank M1. Unfortunately, the requirements laid out for Packard to meet only demanded 200 horsepower, resulting in a similar power-to-weight ratio to the Murray and Tregurtha. An adjustable governor allowed the Packard to spin an extra 300rpm and thereby increase the output to 250 horsepower, but in April 1932 the medium tank T1 (as the medium tank M1 was called when its standardization was revoked in the spring of 1928) nonetheless had its 1T-1330 replaced by a 338-horsepower Liberty V-12 as found in the old heavy tank Mark VIII. This stronger engine bestowed adequate power but caused faults with other components that had not been designed to endure such stress.Hunnicutt, Sherman, 11-6. Neal, 229-32. AGF Board No. 2. Development of Armored Vehicles, volume 1: Tanks, 27-9.

Medium tank M1

Although heavily utilized in Soviet BT and British cruiser tanks well into World War II, the Liberty was not installed in any standardized American designs after the Mark VIII.See Neal, 407-10, 414-45, 477-8, for details on Soviet and British use of imported and domestically-produced Liberty engines The Ordnance Department instead looked toward air-cooled radial aircraft engines as the most suitable compromise for tank use. Robert Insley, a former Army Air Service engineer who in August 1929 became vice president of the Continental Aircraft Engine Company, had begun agitating for the installation of Continental's R-670 7-cylinder radial in tanks as early as 1931, since it was failing to garner significant commercial aviation contracts. The greatest obstacle was generating sufficient cooling airflow: compared to a plane hurtling through the sky, the confined and static setting of a tank's engine compartment was an oppressive environment. The Ordnance Department developed an engine-driven fan during tests beginning in 1932, but it consumed over 25% of the available horsepower. After the Ordnance Department handed the problem over to Continental, that company contacted renowned British engineer Lionel S. Marks, with whose help was designed a cooling fan that required a scant seven horsepower. After a name change to W-670, this engine drove many light tanks, combat cars, and amphibian tractors through the 1930s and 1940s. Wright Aeronautical's stronger R975 Whirlwind 9-cylinder radial was used in the medium tank M2 with a similar cooling solution, though Whirlwind production for armored vehicles was subsequently assigned to Continental as Wright concentrated on production for aircraft.Wagner, 76-8, 87. Green, Thomson, and Roots, 291.

Continental W-670-9A engine

The choice of radial engines was not without debits. Tall by its nature, the radial resulted in a relatively high hull as the propeller shaft needed to clear the fighting compartment floor or turret basket as it angled down from the rear engine to the transmission at the front. Also, if the vehicles had sat idle for six hours or the engines were cold, there was a chance that oil could migrate to the lower cylinders and cause hydrostatic lock if the engine was started. To see if this occurred, it was necessary to turn the engines over by inserting and rotating a hand crank for 40-50 revolutions. If hydrostatic lock was present, the offending oil had to be drained by removing the spark plugs from the lower two cylinders and continuing to turn the engine over with the hand crank.TM 9-731A, 25. TM 9-731AA, 56, 117. TM 9-726, 17. TM 9-727, 27 Furthermore, even with the more efficient cooling fan, the medium tank M2's engine was prone to overheating due to inadequate airflow through the engine compartment.Brockman et al., 16. As the heft of subsequent medium tanks increased, the R975 struggled to keep pace. For example, the medium tank M3 weighed over 20,000 pounds (9,000kg) more than the M2, and suffered from oil consumption and carburetor air temperature issues as well as inadequate room in the engine compartment for cooling airflow to meet the increased demands. Later, though the R975 was improved to produce more power, its output still garnered complaints from crews of the even heavier medium tank M4. Logistically, a handicap of employing solely radial engines was the anticipated inability of their manufacturers to meet President Franklin D. Roosevelt's very ambitious tank production targets, especially when combined with the burgeoning aircraft industry's own requirements.Green, Thomson, and Roots, 290-1. Wheeler, 166. For complaints about the radial power level see White, 66, 90, 93. On 3 January 1942, Roosevelt sent Secretary of War Henry L. Stimson a letter setting a tank production goal of 45,000 vehicles in 1942 and 75,000 in 1943, though more realistic numbers were eventually calculated. See Thomson and Mayo, 60-4. This combination of factors forced the M3 and M4 medium tanks to use no less than five different power units, ranging from the aircraft-derived Wright and Continental radials and Ford GAA to assemblies of multiple automobile engines like General Motors's twinned truck diesels and the Chrysler A57 multibank, which was comprised of five car engines arranged to run as a single unit. Similarly, the light tank M5's development was initiated, in part, to preemptively solve the forecasted shortage of the W-670 radials used in the light tank M3.Hunnicutt, Sherman, 74. Hunnicutt, Stuart, 172.

Chrysler A57 Multibank engine

In spite of the improvements done on individual components, wholesale replacement of the country's park of tired and obsolete tanks was a glacially slow process thanks to an isolationist public and depression-induced budgetary stringency. The World War's end and the depression of the following decade caused the government to seek savings from its armed forces. While 1919 saw a total of $11 billion spent on the Army and Navy, by 1924 this figure had plummeted by around 95%.Matheny, 45. In fiscal year 1922, military appropriations were cut by over 16% from the previous year's amount, and expenditures did not reach the 1921 level again until 1938.Odom, 81-2. During fiscal years 1920-1928, excluding funds contracted to Christie, $982,675 was spent in on medium tank development.Neal, 232-4. This can be contrasted to the projected $52,000 price tag to construct one medium tank M1 prototype in 1927.Hunnicutt, Sherman, 14-5. Trying to replace a single armored car in a unit had become a nine-month ordeal by 1931, yet the Army's budget was decreased by a further 20% over the next three years.Johnson, "From Frontier Constabulatory to Modern Army," 178. Yeide, Fighting Patton, 46. In 1932, $250,000 was earmarked for tank procurement, or 0.06% of that year's Army budget.Yeide, Fighting Patton, 46. The Ordnance Department's portion of the Army budget from 1922-35 only totaled 3.5%, ballooning to 25% in 1939 as the country scrambled to make up for lost time with war erupting in Europe.Morton, 11.

The Army Air Corps absorbed a large portion of the consistently-shrinking depression-era funding. 1933, for example, saw 20% of the Army budget funneled to the Air Corps.Odom, 102. Looking at the years from 1925-1940, the Army spent almost 48% more money on the air element versus improving or replacing ground equipment.Johnson, "From Frontier Constabulatory to Modern Army," 182.

International conferences and treaties also helped sway public and official opinion away from the urgency of national defense. In August 1928 the United States and France brokered the Kellogg-Briand Pact, which ultimately accumulated forty-five other countries. Signatories pledged to "renounce" war "as an instrument of national policy in their relations with one another."National Museum of American Diplomacy, <https://diplomacy.state.gov/the-kellogg-briand-pact/>; Office of the Historian, Foreign Service Institute, United States Department of State, <https://history.state.gov/milestones/1921-1936/kellogg>. Quoted in Lillian Goldman Law Library, Yale Law School, <https://avalon.law.yale.edu/20th_century/kbpact.asp>. A World Disarmament Conference convened in Geneva in February 1932, and in a bid to kickstart progress President Herbert Hoover sent a memorandum to Secretary of State Henry L. Stimson which included the suggestion that--along with aircraft carriers, submarines, poison gas, military aviation (except for reconnaissance), and mobile land guns over 6" (15cm) in caliber--the United States should "[a]bolish all tanks."Quoted in Office of the Historian, Foreign Service Institute, United States Department of State, <https://history.state.gov/historicaldocuments/frus1932v01/d121>. Three years later, in an attempt to prevent the United States's involvement in another foreign conflict, Congress passed the first of a series of Neutrality Acts that forbade or restricted financial transactions with warring nations.Office of the Historian, Foreign Service Institute, United States Department of State, <https://history.state.gov/milestones/1921-1936/neutrality-acts>. For more on the impact of isolationism and treaties during this time, see Johnson, "From Frontier Constabulatory to Modern Army," 175-9; Hofmann, Through Mobility We Conquer, 168-9; Matheny, 46, 69; Gerhard L. Weinberg, "The Politics of War and Peace in the 1920s and 1930s," in The Shadows of Total War, Chickering and Förster, eds., 31-2.

These factors exerted a strong influence on American tank development. The US produced a pitiful thirty-five tanks from 1920-35, and from 1925-39 the Army budgeted funds for building, on average, a single pilot prototype per year.Thomson and Mayo, 224; Blumenson, The Patton Papers 1885-1940, I: 1048; Green, Thomson, and Roots, 195. Yeide, Fighting Patton, 46. Cameron, Mobility, Shock, and Firepower, 25, differs with Green, Thomson, and Roots by claiming the years included 1925-31. This is in spite of MacArthur rating the Army's tanks in 1933 as "completely useless" for battle save for a few experimental vehicles, and with war plans not providing for the initiation of tank production until seven months post-mobilization.Quoted in D'Este, 293; Odom, 103. Gole, 3. Cameron, Mobility, Shock, and Firepower, 133. The German military attaché in Washington, D.C., shared MacArthur's conclusion, reporting in 1934 that, save for a mere handful of machines built within the past few years, every American tank was "completely obsolete and worthless in battle against armies with modern equipment," and he estimated it would tank the country a year to begin tank mass production.Yeide, Fighting Patton, 46-7.

This manufacturing drought meant that the Army was unable to produce sufficient machines to fill out its tables of organization. Most Regular and National Guard tank companies were only allocated eight tanks apiece, therefore being able to field but a single platoon with three spare vehicles. Some with less luck, like the Wisconsin National Guard's 32d Tank Company, were converted to transport companies for a number of years. Worse yet, the 5th and 6th Tank Companies were simply idled from the time the M1917 was declared obsolete until earnest preparations for World War II were underway in 1940. Upon fielding of the light tank M2 in the mid-30s, most National Guard companies were given two tanks on which to train. A heavy tank regiment was approved in 1927, but was only staffed with one out of its nine allotted tank companies. When the Mark VIII was removed from operation by 1932, the formation was redesignated as a medium tank regiment since there was no new heavy tank design to replace it. As there was also no standardized medium tank in service, the unit was instead equipped with various experimental machines.Lemons, Organization and Markings of United States Armored Units 1918-1941, 33, 43, 56, 59, 65, 68-9, 98, 119, 124-5.

Six-ton tank M1917

Funding issues affected the mechanization of artillery in addition to tank development. Research on trucks and tractors was largely curtailed after 1922, and almost all motorized artillery units being used for testing were eliminated. Self-propelled mounts had also come to be considered too large, heavy, unmaneuverable, and unreliable. Concerns about the durability of the contemporary automotive state of the art led the War Department to say in 1928 that horse-drawn artillery would be employed with the division indefinitely. Major General Robert M. Danford, who had become Chief of Field Artillery in 1938, expounded in 1939 that towed artillery was preferable to self-propelled, and that eliminating the horse from field artillery units was "an unsound policy." Dastrup, King of Battle, 188-90, 192-3. Quoted on p.193. Indeed, despite Major General Snow's 1920 directive to see if all Army field artillery could be mechanically drawn, by 1938 40-60% of Army artillery was still towed by horse teams.Green, Thomson, and Roots, 203.

The US Marine Corps started looking into mechanization between the wars. King armored cars and the little M1917 gave the Marines their first experience with armored vehicles, with a light tank platoon of five M1917s being fielded until November 1928. Weight and size limitations imposed by the Navy's cargo cranes and tank lighters led to experiments with small numbers of unreliable, diminutive designs by the Marmon-Herrington company before it was decided that standardization with the Army would be beneficial.Joseph H. Alexander, "Marine Corps Armor Operations in World War II," in Camp Colt to Desert Storm, 187-9. Estes, Marines Under Armor, 2-26. Gilbert, Marine Tank Battles in the Pacific, 18-21. M2A4 light tanks were therefore procured starting in 1940, and M3 light tanks were acquired the next year.Alexander, 198. Estes, Marines Under Armor, 28-9, 206. Gilbert, Marine Tank Battles in the Pacific, 21, 25.

CTL-3

Foreign armored forces saw action in the late 1930s, and America looked to these conflicts to extract relevant lessons. The Sino-Japanese and Spanish Civil Wars, for example, both featured the use of tanks and experimentation with armored unit tactics, equipment, and organizations. Notably, Soviet BT-5 tanks using Christie's suspension design debuted with the Spanish Republicans on 13 October 1937.Esdaile, 237. Hooton, 148. Candil, 113-4. Though the United States invested special interest in observing the Spanish conflict, many confounding factors hindered extracting relevant lessons on the use of tanks. Armored actions in Spain were marked by insufficient training and experience of crews, poor tactics and choices of ground on which to employ the machines, muddled doctrines, and resupply of vehicles that was sporadic enough to make organization and planning difficult.Cortada, xviii-xix, 212, 219-20. Esdaile, 230, 288, 306-7. Hooton, 20, 126, 130, 148, 173-4, 183. Candil, 31, 95-6, 107-8, 112-4, 115, 126, 128, 146-7, 162, 176-7. Habeck, 257.

Despite the idiosyncrasies associated with the Spanish Civil War, US Army Chief of Staff General Malin Craig drew the conclusion that the power of defensive weapons such as the antitank gun had grown paramount, and therefore that the tank remained an auxiliary for aiding the infantry. The 1939 edition of the Army's FM 100-5 Tentative Field Service Regulations, Operations echoed the post-Great War tank doctrine of having medium tanks disable antitank weapons while light tanks followed to defeat machine guns and otherwise assist the infantry advance.Odom, 138-9, 142, 150. Cortada, 60-1, 83, 223. Candil, 178-9. Conversely, German first-hand experience in the Spanish Civil War showed them that their light, machine gun-armed tanks were unable to compete with enemy gun-armed machines, but Germany did not extract other wide-scale lessons on tank use due to the issues listed above.Jentz, ed., Panzer Truppen, 1: 46. Habeck, 256-7.

Thus, right up to the outbreak of the century's second pandemic war, US Army leadership was still reluctant to organize its few tanks into all-arms mechanized teams. Additionally, the Infantry and Cavalry chiefs both disagreed with the idea of transforming extant infantry or horse cavalry formations into mechanized units."Armored Force, Command, and Center," 5. Nenninger, 57. Meanwhile, though Germany's army would continue to be a mostly foot- and horse-mobile force, it persevered with its mechanization scheme and by September 1939 had formed six armored divisions in which were concentrated the majority of its tanks.On Germany's reliance on horses, see Dinardo. Ogorkiewicz, Armoured Forces, 72-4. Jentz also includes Panzer-Division Kempf, for a total of seven Panzer-divisionen. Jentz, ed., Panzer Truppen, 1: 88-92.

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World War II: Obscurity to Maturity

Practice maneuvers performed by the US Army in 1939 and 1940 as well as the shock of Germany's Panzer-divisionen racing through Poland and France spotlighted the need for reform, so the Army created the Armored Force on 10 July 1940, ignoring protests from the Infantry and Cavalry chiefs. A new branch of the Army still could only be created by an act of Congress; to circumvent this obstacle as well as the National Defense Act of 1920's legal assignment of tanks to Infantry, the War Department established the Armored Force "[f]or the purposes of service test."Greenfield, Palmer, and Wiley, 56. Gillie, 162-3. Johnson, Fast Tanks and Heavy Bombers, 144. Gabel, The U.S. Army GHQ Maneuvers of 1941, 23-4. Cameron, Mobility, Shock, and Firepower, 255. Yeide, The Infantry's Armor, 3. "Armored Force, Command, and Center," 9. House, 102. Hofmann, Through Mobility We Conquer, 265-7. In essence, though, the Armored Force was a new branch that combined the separate armored assets of the Cavalry and Infantry, totaling four hundred light and eighteen medium tanks, and with its inception the organization of US mechanized forces was finally modernized.Gillie, 170. At the same time, an Armored Forces Board was established to further the development and evaluation of tactics, transportation, equipment, and armament used by armored units."Armored Force, Command, and Center," 93. The forward-thinking Chaffee, by now a brigadier general who had risen to command the 7th Cavalry Brigade (Mechanized), was chosen as chief of the new organization. Cavalry was further entwined with the Armored Force when the 7th Cavalry Brigade (Mechanized) was tapped to become the nucleus of the 1st Armored Division. Prodigal son Patton also returned to armor by again taking command of an armored brigade, this time the 2d Armored Brigade of the 2d Armored Division. The division itself and the I Armored Corps would both be waypoints on his rise to army command.Patton's son George would take command of the 2d Armored Division in August 1975, marking the first time that a son would command the same US Army division as his father. See Sobel, 205.

The Armored Force was initially composed of the I Armored Corps, formed from the 1st and 2d Armored Divisions, and the separate 70th Tank Battalion (Medium). Later the Armored Force would suggest an armored corps consisting of two armored divisions, a motorized division, and support elements, but this would not come to fruition."Armored Force, Command, and Center," 9, 32. Cameron, Mobility, Shock, and Firepower, 253, 372. The armored divisions included an armored brigade made from two three-battalion light tank regiments, a two-battalion medium tank regiment, and a two-battalion artillery regiment; a two-battalion infantry regiment; another artillery battalion; and reconnaissance, engineer, maintenance, and support elements. The six light tank battalions and two medium tank battalions yielded a total of 287 light and 120 medium tanks."Armored Force, Command, and Center," 15-6, 32. Cameron, Mobility, Shock, and Firepower, 253-4. Christopher R. Gabel, "World War II Armor Operations in Europe," in Camp Colt to Desert Storm, 146. Gabel, The U.S. Army GHQ Maneuvers of 1941, 24-5. Ogorkiewicz, Armoured Forces, 88.

Maneuvers in Louisiana and the Carolinas in the fall of 1941 exposed problems with this organization, including the untenability of the ratio of armor to infantry and the existence of coordination problems between the separate arms. The armored division was therefore redrawn on 1 March 1942 to be more in line with European trends. Two armored regiments were now fielded, each composed of one light and two medium tank battalions for a total of 232 medium and 158 light tanks and 14,618 personnel, up from the 11,200 men of the earlier iteration. A third battalion was added to the infantry regiment, and the artillery chain of command was simplified with the creation of a divisional artillery headquarters for all three artillery battalions. An organizational breakthrough came with the replacement of the armored brigade with two "combat commands," A and B. Subordinate units were not permanently assigned to the combat commands, but they could accept different battalions or other formations as different missions dictated. This bestowed upon the armored division a large degree of flexibility, but confusingly the regimental headquarters acted as a supply dump and maintenance resource for its subordinate battalions no matter to which combat command they were assigned."Armored Force, Command, and Center," 28-9, 32. Cameron, Mobility, Shock, and Firepower, 373-7. Gabel, "World War II Armor Operations in Europe," 146-7. Gabel, The U.S. Army GHQ Maneuvers of 1941, 121-2, 149, 175-9. Bellanger, 1. Ogorkiewicz, Armoured Forces, 89-90.

In response to lessons learned during the armored divisions' combat debut in North Africa, the table of organization and equipment was again redone on 15 September 1943. The number of tank battalions was reduced to three, yielding equal numbers of tank, infantry, and artillery battalions. Tank battalions were reorganized to have one light and three medium tank companies. The smaller number of tank battalions lowered the number of tanks to a total of 168 medium and 77 light tanks, and there were 10,936 personnel in the division. A third, smaller combat command headquarters, Reserve Command, was instituted to handle units unassigned to Combat Commands A or B. The armored and infantry regimental headquarters were dispensed with, the combat commands becoming the only headquarters between battalion and division level. All armored divisions except the 2d and 3d Armored Divisions would adopt this new "light" 1943 structure; those two divisions remained similar to the 1942 "heavy" table."Armored Force, Command, and Center," 32-4. Cameron, Mobility, Shock, and Firepower, 382-5. Gabel, "World War II Armor Operations in Europe," 153-5. Bellanger, 1. Ogorkiewicz, Armoured Forces, 92-3.

In practice, the flexibility offered by the combat command organization was not always utilized by division commanders. Some preferred to have units permanently assigned to specific combat commands, while others used all three combat commands as equal-strength formation. The 5th, 8th, 13th, and 20th Armored Divisions are examples that operated with fixed assignments; while the 5th, 7th, 8th, 9th, and 12th Armored Divisions utilized the Reserve Command in combat. This option usually necessitated adding personnel to the Reserve Command headquarters: since it was intended to simply keep track of unassigned units, its staff was smaller than those of Combat Commands A and B.Ogorkiewicz, Armoured Forces, 93. Bellanger, 69-71, 74-6.

Army armor doctrine was innovated along with its organization. Instead of using tanks as purely infantry support devices, according to the March 1942 edition of FM 17-10 Armored Force Field Manual: Tactics and Technique, "The role of the Armored Force and its components is the conduct of highly mobile ground warfare, primarily offensive in character, by self-sustaining units of great power and mobility...The most suitable areas for the employment of Armored Force units are on the open flanks or through existing gaps created by penetrations of the enemy's positions...The most decisive results will be gained from the grouping of overpowering masses of armored units and launching them against vital areas deep in the hostile rear."FM 17-10, 1, 3-4. The footsoldier's leash on the tank had finally been cut.

As a concession to the Infantry's loss of its integral armor, General Headquarters (GHQ) tank units were also created to help reinforce specific operations. From the start, these were intended for infantry support, and the chiefs of Infantry and the Armored Force were to cooperate in creating tactics for them.FM 17-10, 2, 340-2. Greenfield, Palmer, and Wiley 67. Jarymowycz, 72. Johnson, Fast Tanks and Heavy Bombers, 145. "Armored Force, Command, and Center," 44-5. Although conceivable, there were no instances of separate tank battalions being attached to armored divisions in Europe. See General Board, European Theater, Separate Tank Battalions, 4; Greenfield, Palmer, and Wiley, 328; Cameron, Mobility, Shock, and Firepower, 384; and Yeide, Steel Victory, 5. The GHQ tank battalions were renamed "separate" tank battalions after the Army's March 1942 reorganization eliminated GHQ as well as the branch chiefs. Although only fifteen separate tank battalions were initially planned, by early 1943 the Army had created forty-eight tank battalions in armored divisions versus sixty-three separate tank battalions; by late 1944 the ratio was sixty-five separate battalions to fifty-four in armored divisions. Seventy-four independent battalions would eventually be formed along with smaller separate units, including tank companies.Greenfield, Palmer, and Wiley, 333. Johnson, Fast Tanks and Heavy Bombers, 146. Yeide, Steel Victory, 7. Cameron, Mobility, Shock, and Firepower, 481. Yeide, The Infantry's Armor, 6. A total of ten armored group headquarters, similar in personnel to the combat command headquarters of the armored division, were created to handle more than one separate tank battalion."Armored Force, Command, and Center," 45-6. Cameron, Mobility, Shock, and Firepower, 494. Gabel, "World War II Armor Operations in Europe," 155-6.Yeide, Steel Victory, 7-8.

On the other hand, the Cavalry was totally divorced from tank doctrine after the creation of the Armored Force. The branch had had a combined-arms mechanized cavalry regiment in service since 1932 which had managed to grow into a brigade while simultaneously performing pioneering mechanization experimentation, but the Cavalry was ultimately unwilling to totally put the trusted horse to pasture until it was too late. Indeed Major General John K. Herr, who became the final Chief of Cavalry in March 1938, was a staunch advocate of the horse up to his death in 1955. Though he campaigned for the expansion of mechanized cavalry and was denied by the War Department of an advanced mechanization course at the Cavalry School, he steadfastly refused to form further mechanized cavalry units at the expense of existing horse units.Gillie, 138-9. Johnson, Fast Tanks and Heavy Bombers, 136-40. Jarymowycz, 67-8, 71. Yeide, Steeds of Steel, 21-6. "Armored Force, Command, and Center," 5. Morton, 54, 56-9, 64-81, 83-100, 111-4, 193-203, 217-9. Grow, "Part 4," 38-42. Hofmann, Through Mobility We Conquer, 227-8, 236-7, 243-9, 260, 266-7, 275, 279. Gabel, The U.S. Army GHQ Maneuvers of 1941, 29-30. Truscott, 155-7.

Concurrently with the elimination of GHQ and the branch chiefs, Army Ground Forces (AGF) was created on 9 March 1942 to manage ground combat elements, including the Armored Force. Former GHQ Chief of Staff Lieutenant General Lesley McNair was placed in command of the new organization.Calhoun, 245-6. Greenfield, Palmer, and Wiley, 31, 152. Gabel, "World War II Armor Operations in Europe," 145. Cameron, Mobility, Shock, and Firepower, 369-71. The Armored Force was renamed the Armored Command on 2 July 1943 to avoid confusion with the Army Air, Ground, and Service Forces, which enjoyed a degree of independence that the Armored Force did not after its subordination to AGF. A month later the specialized armored corps formation was eliminated in favor of corps headquarters that could be assigned different units as needed, similar in concept to the combat commands of the armored division. I Armored Corps was stood down, and the other three armored corps that had been formed, II, III, and IV Armored Corps, were transformed respectively into the XVIII, XIX, and XX Corps."Armored Force, Command, and Center," 108-9, 33-4. Greenfield, Palmer, and Wiley, 408-9. Gillie, 250-1. Bellanger, 1. Gabel, The U.S. Army GHQ Maneuvers of 1941, 188-9. Gabel, "World War II Armor Operations in Europe," 153-5. Cameron, Mobility, Shock, and Firepower, 398-400, 382-5. Ogorkiewicz, Armoured Forces, 90-3. Wheeler, 171. On 19 February 1944, the Armored Command was downgraded to the Armored Center. The Armored Center, in view of the policy to attach armored units directly to the command of regular corps or armies instead of to the defunct specialized armored corps, was placed under the Army's Replacement and School Command but kept the power, directly under AGF, to inspect armored units and to recommend changes to armored organization, doctrine, training and training literature, and equipment. AGF influence on armor policy grew as that of the Armored Force/Command/Center declined."Armored Force, Command, and Center," 109-10. Gillie, 254-5. Greenfield, Palmer, and Wiley, 410. Cameron, Mobility, Shock, and Firepower, 400-1. Hofmann, Through Mobility We Conquer, 288.

The interest taken in forming American armored units naturally spurred thought on how to defend against enemy mechanized forces. August 1940 Army maneuvers and the German "Blitzkrieg" indicated that passive, defensive antitank tactics would fail when trying to tackle a maneuvering armored enemy. The Army's Infantry, Cavalry, and Artillery branches--but notably not the Armored Force, which considered its offensive-minded spirit anathema to this inherently defensive mission--all clamored to take over the responsibility for antitank duties, so Army Chief of Staff General George Marshall took action in May 1941 by forming a GHQ Planning Branch under Lieutenant Colonel (later Major General) Andrew D. Bruce to study the antitank problem in isolation from any branch prejudices. The arrived-at solution was to centralize all extant antitank battalions along with newly-formed antitank units under GHQ using an aggressive doctrine prepared by a Tank Destroyer Tactical and Firing Center established at Fort Meade, Maryland.Gabel, Seek, Strike, and Destroy, 11-18. Gabel, The U.S. Army GHQ Maneuvers of 1941, 31-3, 175-6. Dunham, 1-6. Yeide, The Tank Killers, 6-7. Gill, 10-1. Odom, 150-2, 158. Commanded by Bruce, the Center espoused doctrine based on the assumption that centrally-held towed or self-propelled antitank guns would be able to offensively concentrate on and defeat Germany's tank attacks once those attacks had broken through the friendly front line, using organic reconnaissance assets to scout firing positions and find the enemy force. The tank destroyers were to hold back if the enemy was accompanied by strong infantry forces or artillery fires, though, since the basis behind their creation was quite simply the destruction of hostile armor.Gabel, Seek, Strike, and Destroy, 26. Yeide, The Tank Killers, 8-9. FM 18-5, 8, asserts that "tank destroyers are ill suited to close combat against strong forces of hostile foot troops." On the other hand, FM 18-20, 50, notes that self-propelled tank destroyers firing HE may deal with "moderate infantry attacks" if assisted by their security section machine guns and a few riflemen. FM 18-21, 68, says that, when the machine guns of towed tank destroyers' prime movers are added to this mix, "many" infantry attacks can be stopped. These tactics were, as far as their proponents were concerned, successfully tested in the 1941 Louisiana maneuvers, but the rules and umpiring were not necessarily realistic.General Board, European Theater, Study of Tank Destroyer Units, 12. Gabel, Seek, Strike, and Destroy, 9, 14-17. Gabel, The U.S. Army GHQ Maneuvers of 1941, 89, 122-4, 149, 170-1, 191-2. Dunham, 4. Baily, 20-1. Cameron, Mobility, Shock, and Firepower, 350-3. House, 145. Calhoun, 240-4. Gill, 11. For criticism of the rules and umpiring, see Cameron, Mobility, Shock, and Firepower, 353-7; Yeide, The Tank Killers, 5-6; Gabel, Seek, Strike, and Destroy, 14-17; Gabel, The U.S. Army GHQ Maneuvers of 1941, 48-9, 125-6, 148-9, 175-6; Adams, 78-80; and Farago, 158, 160-8. Calhoun, 229-31, alleges that rules for the antitank guns were meant to simulate more powerful ordnances that were being designed.

Unfortunately for the tank destroyers, the Germans were not so kind as to commonly provide massed tank attacks, instead usually preferring to attack with concentrated combined arms forces. Likewise, instances of encountering large numbers of enemy tanks became increasingly rare as the war progressed in Europe, and were rare for the almost the entirety of the Pacific campaign.Guderian, 24. von Mellenthin, 20. Citino, 30-2. Macksey, Tank versus Tank, 60, 64. Jentz, ed., Panzer Truppen, 1: 77. Knight, A13 Mk.I & Mk.II Cruiser Tanks, 239, 265. Jarymowycz, 256. Yeide, The Tank Killers, 43. Gill, 36. "Armored Force, Command, and Center," 14. House, 112. Another factor confounding the use of the new arm was that field commanders often misunderstood or ignored the prescribed tank destroyer doctrine; divided up tank destroyer units to support other formations, thereby preventing them from being massed as intended; and frequently forced tank destroyers to perform missions for which they had been neither designed nor trained, for example using self-propelled tank destroyers as assault guns or ersatz tanks.Baily, 54-5, 58-9. Yeide, The Tank Killers, 68. Greenfield, Palmer, and Wiley, 426. Cameron, Mobility, Shock, and Firepower, 416-7, 496-8. Gill, 18, 23-4, 36-7, 60, 72, 73, 76-9.

When the tank destroyers first saw action in Tunisia, it was difficult to impossible to use them offensively as intended,Gabel, Seek, Strike, and Destroy, 42. Gill, 36-7. Calhoun, 280-1. but tactical doctrine and equipment designs forged ahead. The Army's first, indeed only, purpose-built self-propelled tank destroyer was the 76mm GMC M18, which did not appear until July 1943. Before this the tank destroyer forces had used interim designs based on existing vehicles, including the 37mm GMC M6, 75mm GMC M3, and the 3" GMC M10. Towed guns were also touted, for example by McNair and Major General Omar Bradley, due to price, shipping efficiency, and lessons learned in North African combat: concealment was key for towed guns, and in the desert it was easy to dig in and hide the relatively small guns then in use. Once the battle moved to Europe, though, it became apparent how much more useful self-propelled tank destroyers were, and many towed battalions were transformed into self-propelled units. Preferred by both Marshall and Bruce, self-propelled mounts were more beneficial since antitank guns had grown in size and weight, meaning it was more difficult to dig them in and conceal them in the European landscape. The taller self-propelled vehicles also offered advantages in field of vision and firing height.Baily, 21-2, 58-9, 105-6. Calhoun, 233-7. Gill, 16, 37-8, 56-7. Hofmann, Through Mobility We Conquer, 282. General Board, European Theater, Study of Tank Destroyer Units, 10. Gabel, Seek, Strike, and Destroy, 27-8. Cameron, Mobility, Shock, and Firepower, 427. House, 146. Postwar historical analysis indeed suggests that towed guns were more effective than tanks in antitank defense in the North African fighting. See Rowland, 128-36, 147-8.

3" gun motor carriage M10

As the assumptions of the tank destroyer doctrine were realized to be invalid, the Tank Destroyers' influence quickly waned: the Tank Destroyer Tactical and Firing Center moved to Camp Hood, Texas, in January 1942 and was rechristened the Tank Destroyer Command that March. However, it was downgraded to the Tank Destroyer Center in August 1942, and in October of the next year the Tank Destroyers had to fight against AGF's desire to roll them into the Field Artillery. This merger was resisted by both the Tank Destroyers and the Field Artillery due to the different tactics used by the two arms, but Tank Destroyer enlisted men nonetheless became Field Artillery personnel.Gabel, Seek, Strike, and Destroy, 44, 46. Dunham, 20, 35. Gill, 12, 41-2. Cameron, Mobility, Shock, and Firepower, 407, 431-2. The advent of more powerfully-armed tanks added fuel to the fire by erasing the armor penetration advantage the Tank Destroyers had held over earlier tank designs. Despite the issues with doctrine and their frequent use in missions foreign to their training, the Tank Destroyer troops provided yeoman service and ended World War II with a loss exchange ratio firmly in their favor.Yeide, The Tank Killers, 250. Dunham, 51.

American armor lagged technologically as well as organizationally at the start of World War II. Standardized and accepted tanks had been few and far between in the 1930s, and included the Infantry's M2 light tank and the Cavalry's M1 and M2 combat cars, which all used essentially the same hulls. Although these machines' reliability had increased over the M1917 to the extent that in 1935 the light tank company was redrawn to be made up of three five-tank platoons and a headquarters platoon of only three tanks, their battlefield value was questionable as all of these vehicles had hitherto been armed solely with machine guns.On the light tank company modification, see Lemons, Organization and Markings of United States Armored Units 1918-1941, 83.

Light tank M2A2

The US finally got a standardized medium tank in 1939 with the arrival of the M2, a design armed with a 37mm gun and bristling with more machine guns than crewmen. Most European countries, in contrast, had tanks in service that possessed more powerful weapons. In particular, Germany's Panzerkampfwagen (Pz.Kpfw.) IV was armed with a 75mm gun, and on 5 June 1940 Chief of Infantry Brigadier General Asa L. Singleton advised the Ordnance Department that the medium tank M2 was lacking compared to this German machine and requested an American tank that matched this vehicle in armament.Hunnicutt, Sherman, 45. Ogorkiewicz, Technology of Tanks, I: 24. Zaloga, Armored Thunderbolt, 20. Baily, 5. Gillie, 170-1. Chamberlain and Ellis, M4 Medium, 53-4. This reversed Singleton's 1938 opinion that considered a 75mm gun medium tank unnecessary despite reports of German experimental tanks armed with 88mm guns.Green, Thomson, and Roots, 201. Curiously, though, the Germans apparently did not actually have any tanks armed with an 88mm gun until Tiger prototypes were constructed in 1942. See Spielberger and Doyle, Tigers I and II and their Variants, 27; Jentz and Doyle, D.W. to Tiger I, 23-8, 67-9; and Ludvigsen, 173, 177.

Medium tank M2

In order to get the weapon to the field as quickly as possible, production went forward on the medium tank M3, which mounted its 75mm gun in the right sponson. Fortuitously a similar setup had been under evaluation since April 1939 when a 75mm howitzer was installed in the sponson of a surplus prototype of the M2 medium tank. Production of the M3 began as soon as possible to quickly ship the new tanks to the British, who were embroiled in the fight against Panzergruppe Afrika.Hunnicutt, Sherman, 35, 46. The urgency was such that, before the Lend-Lease Act was passed, the British spent over $16.5 million on improvements to the American factories with which they contracted to build the tanks.David Doyle, M3 Lee Grant, 27. Similarly, the British were sometimes given a higher priority for medium tanks than the US Armored Force, and tank production and delivery could be so hurried that defects which occurred during manufacturing and shipping sometimes caused significant delays while these faults were repaired in field workshops.Cameron, Mobility, Shock, and Firepower, 264; David Doyle, M3 Lee Grant, 148; Ross, 208; Smithers, Rude Mechanicals, 122. For the need to repair newly-delivered tanks, see Coombs, 89, 91; and Hopkins, 63.

Once in the desert, ammunition issues cropped up for the 75mm gun. Its armor-piercing M72 round struggled with the face-hardened armor on enemy tanks. Until the capped armor-piercing M61 projectile was available in the Middle East, an in-theater fix instigated by the Royal Army Ordnance Corps's Major Northy and supported by the US Army's Major G.B. Jarrett saw the conversion of captured German 7.5cm Kanone Granate rot Panzer capped and ballistic capped armor-piercing (APCBC) shells to US 75mm cartridge cases. In addition, the World War I-era fuzes on available 75mm high-explosive ammunition were a source of trouble. They had aged poorly enough that some shells detonated in the guns during practice firing, leading to a number of deaths. Also, the fuzes had been intended for indirect fire, and would often not actuate if the shell did not impact directly. Better fuzes manufactured by France for World War I were sourced from Syria to solve these problems.Hunnicutt, Sherman, 89-90. Jentz, Tank Combat in North Africa, 54. Taylor, Firing Now!, 110.

While the British accepted American vehicles, they were apparently dissatisfied with the Ordnance Department's nomenclature system where the first of each type of standardized item would be named "M1" and subsequent models would simply sequentially increase. Instead they started naming US tanks after American Civil War generals. The light tank M3 was dubbed Stuart, and the medium tank M3 would be either the Lee or the Grant, respectively, depending on if it was topped with the original US Army Ordnance Department 37mm gun turret or the shorter and longer turret for British consumption designed by L.E. Carr. On 28 August 1942 British Prime Minister Winston Churchill himself issued instructions on the naming of American tanks, and dictated that "General" should not be used as it might cause confusion with active commanders.Fletcher, The Great Tank Scandal, 88. Hunnicutt, Sherman, 47. Taylor, <http://www.militarymodelling.com/news/article/'what's-in-a-name'/4580/>. Despite their own convoluted tank nomenclature scheme, Since 1940, Churchill had been advocating for names for British tanks as well; this was finally realized as policy in September 1941. See Knight, A13 Cruiser Mk.V Covenanter Tank, 76; Taylor, The Second World War Tank Crisis, 4-5, 220. the British may indeed have had a point about the user-unfriendliness of the American way: it would be plausible, for example, to see on the battlefield simultaneously a light tank M3, which used the same 37mm gun as the medium tank M3, which itself was armed with the 75mm gun M3, which fired the same ammunition as the gun on the 75mm GMC M3, which used the gun mount M3 and was based on the half-track personnel carrier M3, whose lineage could be traced back to the scout car M3.

Scout car M3

Whatever it was called, both the British and Germans were impressed with the Lee/Grant upon its combat debut: The British were happy with its armor, armament, and reliability compared with their Crusader cruiser tanks mounting the 2 pounder gun, and likewise Generalleutnant Erwin Rommel rated it higher than all tanks in the theater except the long-barreled Pz.Kpfw.IV Spezial.Knight, A15 Cruiser Mk.VI Crusader Tank, 70-3, 78, 80, 83, 97, 112. The Soviets were also impressed with the reliability of both the medium tank M3 and light tank M3. See Kavalerchik, 155. For the German view, see von Mellenthin, 111, 117; and Liddell Hart, The Rommel Papers, 185, 196-7, 206-7, 330. Some US troops fielded a less favorable view, however. See Cameron, Mobility, Shock, and Firepower, 391; and Adams, 64. Once the ammunition difficulties were worked out, its 75mm gun was able to take on enemy armor as well as antitank guns; to this point enemy guns had been difficult for British tanks since their 2 pounder gun did not have an effective high-explosive shell issued, and their machine guns were not supplied with armor-piercing ammunition for penetrating enemy antitank gun shields.Beale, 96-7. Ross, 173. Fletcher, The Great Tank Scandal, 90, 109. Buckley, 73-5, 145. Hunnicutt, Sherman, 88. Perrett, 86. Zaloga, Armored Thunderbolt, 28. Jentz, Tank Combat in North Africa, 14, 47, 54. Knight, A15 Cruiser Mk.VI Crusader Tank, 33-4, 41. Liddell Hart, The Tanks, 2: 227. House, 125. Taylor, Firing Now!, 51. Forrester, 60-2. The need for a tank mounting a 75mm gun with its concomitant high-explosive capability had been identified as early as May 1940 by British officers digesting the lessons of the battle of France.Knight, A13 Mk.I & Mk.II Cruiser Tanks, 237, 262. In addition, the 37mm guns in both the medium tank M3 and light tank M3 outperformed the 2 pounder against face-hardened armor due to the use of piercing and ballistic caps in 37mm armor-piercing ammunition.Knight, A15 Cruiser Mk.VI Crusader Tank, 51, 67.

Medium tank M3A1 Lee

Before manufacture began on the M3, it was realized that having the 75mm gun in a turret would be preferable to its somewhat unorthodox layout, but neither a turret that could mount a 75mm gun, nor a recoil system capable of handling such a weapon in a tank turret, had yet been designed in the US.Hunnicutt, Sherman, 47. Zaloga, Armored Thunderbolt, 20. Johnson, Fast Tanks and Heavy Bombers, 148. Development of the follow-on 75mm gun-turreted tank, the medium tank M4, commenced immediately upon the completion of the M3's plans, and the first M4A1 was accepted eight months after the first M3. Called Sherman by the British, the M4 was based on the mechanical components of the M3 series, which itself was based on the M2 medium, and the Lee's 75mm gun was retained on the M4.

Medium tank M4A1 Sherman

From the beginning of the Sherman's design process, though, plans had been in place to arm it with a better armor-piercing gun. The Sherman's turret front plate was interchangeable, and it was proposed to use a 105mm howitzer and the 3" gun M7 as well as the 75mm gun. However the 3" gun, which had already been arming prototypes of the M6 heavy tank and which would see widespread service in the GMC M10, turned out to be too unwieldy for the medium tank turret. The remedy to this problem, a weapon that was ballistically identical to the 3" gun M7 but light and compact enough to fit in the Sherman's turret, was produced by August 1942.Hunnicutt, Sherman, 198-9. One thousand Shermans armed with this new weapon, which was designated the 76mm gun M1, were desired by the Ordnance Department, but the Armored Force considered the design ergonomically unworkable.Hunnicutt, Sherman, 200, 202. Baily, 83.

Heavy tank M6

A radial engine solving many of the issues posed by the Sherman's R975 was unveiled in 1942. Caterpillar developed their D200A 9-cylinder radial by starting with the crankshaft, cylinders, connecting rods, and supercharger of the Wright Cyclone engine also used in the heavy tank M6, and combining these parts with their own pistons, cylinder heads, crankcases, and fuel injection and lubrication systems.Hunnicutt, Sherman, 167. Stansell and Laughlin, 216. The D200A was more powerful than previous medium tank radials and could consume fuels ranging from diesel to low-octane gasoline. Its pistons were cooled by oil sprayed onto their undersides, and oil accumulation in the combustion chambers could be cleared by running the engine starter with the governor in the off position. Also, a transfer case lowered the propeller shaft connection to near the bottom of the engine.TM 9-1756A, 8, 11. TM 9-756, 15, 120. The new design was enticing enough that one thousand D200As, called the RD-1820 Ordnance Engine by the Ordnance Department, were authorized in January 1943. Plans were made to mount them in 775 tanks for extended testing, and the first medium tank M4A6 powered by the RD-1820 was completed in October 1943. In the end, only seventy-five M4A6s were built as the Army looked to simplify its logistical needs, balking at the addition of another engine type and eschewing diesel in favor of gasoline, with the M4A3 and its Ford V-8 becoming the preferred medium tank.Hunnicutt, Sherman, 169. Stansell and Laughlin, 216.

RD-1820 Ordnance Engine

The Army continued to work on new medium tanks even immediately after the introduction of the Sherman. One of the earliest efforts started as a light tank design mooted in early 1941, but weight increases during development led to its standardization as the medium tank M7 in August 1942. Major General Jacob Devers, an artillery officer tapped to command the Armored Force on 1 August 1941 as Chaffee succumbed to cancer, was enthusiastic about this vehicle, suggesting that manufacture of the Sherman be curtailed if required to get the M7 into service more quickly. The Quad Cities Tank Arsenal in Bettendorf, Iowa, was created expressly for M7 production by refurbishing adjacent plants bought from three different companies and integrating them under the International Harvester Company, and orders for 3,000 tanks were placed. Unfortunately, tests on the initial vehicles in early 1943 showed that the new tank's performance was inferior to that of the M4A3, and it also offered no advantages in armament or armor over the Sherman. His mind changed, Devers requested on 16 March 1943 that the M7 program be terminated. For an expenditure of sixteen million contemporary dollars, a total of seven standard M7s were built along with six additional tanks modified to try to improve performance.Baily, 33-5. Hunnicutt, Stuart, 199, 206-7. Thomson and Mayo, 251-2. Zaloga, Armored Thunderbolt, 109. Some use was obtained from the Quad Cities Tank Arsenal, as in mid-late 1944 it was used to rebuild and modernize older tanks. See Thomson and Mayo, 258-9.

Medium tank M7

Another replacement program for the Sherman was the T20 design series, which commenced in the spring of 1942. The first prototype completed was the T23, which featured an electric drivetrain similar to that found in the heavy tank T1E1. The engine powered an electric generator which drove a traction motor at each of the rear final drives. This theoretically allowed the engine to run at its most advantageous speed, provided an infinite turning radius and speed range, and even permitted the tank to be driven from the turret or outside using controllers connected to the tank via cables. The T23 performed so well in initial trials that production was begun, but after its own trials the Armored Force declined the tank due to maintenance issues, weight imposed by its drivetrain, the fact that in practice the tank had to go at least 10 miles per hour (16kph) or risk damage to its traction motors, the completely new requirements maintenance crews would be forced to learn, and because overall it offered little advantage over the current medium tank once the 76mm gun was mounted in the Sherman. Nonetheless, two hundred fifty T23s were built, which was enough medium tanks to outfit almost one-and-a-half armored divisions. The European Theater was offered two hundred of the idle tanks in February 1945, but refused them for reasons including maintenance crew training and the new supply line necessary for the novel drivetrain.Hunnicutt, Pershing, 72, 81-2. Baily, 74-82, 137-8. Zaloga, Armored Thunderbolt, 112-3.

Medium tank T23

Though the T23 did not see service, it provided the basis for further developments. Its turret, which had been designed from the start for the 76mm gun, was satisfactorily mated to the Sherman hull.Hunnicutt, Pershing, 73-4. Baily, 84. This solved the ergonomic problems of the earlier 76mm Sherman design, and production of 76mm gun medium tanks began in January 1944 even before prototype testing had completed. 75mm gun tanks were set to be totally replaced on the assembly lines with 76mm gun tanks, but the Armored Command balked. They noted that the 75mm gun fired a more effective high explosive shell, the 76mm gun emitted a blinding muzzle blast, and the larger 76mm rounds resulted in lower ammunition loads and more difficulty in handling the rounds inside the tank.The 75mm HE shell M48 contained a 1.47lb (0.667kg) bursting charge of TNT and produced an average of 0.189 casualty-causing fragments per square foot (0.09m²) at 20' (6.1m) away from the burst, compared with the 0.86lb (0.39kg) TNT bursting charge and average of 0.111 effective casualty-producing fragments per square foot (0.09m²) at 20' (6.1m) away from the burst of the 76mm HE shell M42A1. See TM 9-1901, 356, 359, and TM 9-1907, 128-9. The muzzle blast of the 76mm gun, especially early versions without muzzle brakes, was so obscuring that it was considered a "one shot" weapon. See General Board, European Theater, Tank Gunnery, 37. Hunnicutt, Sherman, 206. Cameron, Mobility, Shock, and Firepower, 462. Baily, 84-5. Zaloga, Armored Thunderbolt, 116. Baily says that Ordnance was opposed to the 76mm gun Sherman, "possibly because it would compete with the T23", which Ordnance was then developing. For an insider's thoughts on such occurrences even decades after World War II, see Brownlee and Mullen, 196-7. Consequently, 75mm gun medium tanks continued to emerge from the Fisher Tank Arsenal through the first quarter of 1945, and the last of these was accepted by the Army that March.Stansell and Laughlin, 19, 21. Hunnicutt, Sherman, 525. Arming the Sherman with the 90mm antiaircraft gun was also briefly considered in 1942, but it was realized that performance degradations resulting from modifications required to make the gun and ammunition manageable inside a medium tank turret would render the upgrade moot.Hunnicutt, Sherman, 212. It should be noted that these developments, stretching back to 1942, began before the Pz.Kpfw.Panther was even designed, and 76mm gun tank manufacture was undertaken before the Panther was seen in the West.Panther first appeared in the West in Italy in August 1943 with I./SS-Pz.Rgt.1 of SS-Pz.Gren.Div.LSSAH, but these tanks returned to Germany without seeing action. Panthers did not actually engage the Allies in the West until tanks of I./Pz.Rgt.4 fought around Anzio in February 1944. See Jentz, Germany's Panther Tank, 144; Zaloga, Armored Thunderbolt, 89; and Jentz, ed., Panzer Truppen, 2: 135-6, 144.

Medium tank M4A3(76)W Sherman

Despite rushing 76mm gun tanks into production, they would not see combat until well into the Normandy campaign. One hundred thirty of the vehicles had made it to England by April 1944, but commanders initially elected not to use them. A 20 April 1944 briefing at Lieutenant General Bradley's headquarters by a representative of the First US Army's Armored Fighting Vehicles and Weapons Section detailed the benefits of the new gun, including greater accuracy and increased armor and concrete penetration. Disadvantages noted included the lower ammunition loads, weaker high explosive shell, no appropriate smoke shell, and target obscuration that might necessitate the tank commander actually dismount in order to sense the shot. The obscuration problem was somewhat ameliorated by using a new propellant mix that lacked potassium sulfate, using new primers that were 19" (48cm) long instead of the earlier 10" (25cm) types, and adding a muzzle brake; but these cons, and the very short time available to train tankers on the new gun, helped to conspire to keep the 76mm gun tanks out of action until Operation Cobra in late July.Baily, 101. Zaloga, Armored Thunderbolt, 129-31, 166. Napier, 242-3. Hunnicutt, Sherman, 206-7. TM 9-1901, 124-5. Layne, "Battle Report for October 1944," 7. Tank commanders continued to complain about obscuration and even injury due to the 76mm gun blast into the 1950s. See Johnson and Rowland, 2, 6, Appendix 1. Combat quickly changed minds in favor of the new tanks: Though even in June 1944 it was intended to field 75mm and 76mm gun tanks in a two-thirds to one-third ratio, by the time of the Rhine crossings in March 1945, approximately 40% of the Shermans in European Theater stocks were armed with the 76mm gun.Hunnicutt, Sherman, 213. Mayo, 336.

By May 1943, there was interest in arming a medium tank with the new 90mm tank gun, so forty of the T23 hulls being manufactured were modified with a torsion bar suspension, a more conventional powertrain, and a 90mm gun turret and designated T25E1; ten similar tanks with a thicker armor base were also constructed and called T26E1. Heavier armor proved more desirable after combat was joined in northwest Europe, so the T26E1 was chosen for production over the lighter T25E1. Testing in 1944 led to revisions to its ammunition stowage, transmission, and brakes, and an improved version with fixes to these issues was named T26E3. The first T26E3s to see combat arrived in Europe in February 1945 among other types of experimental equipment with the Zebra Mission, and the tank was standardized as the M26 the following month.Hunnicutt, Pershing, 13-4, 81, 94, 104, 117, 120. Baily, 75, 134. Zaloga, Armored Thunderbolt, 121, 287. Heavier armor than that found on the Sherman was also desired for some operations by British personnel after experience in Normandy. See Forrester, 103-4.

Medium tank M26 Pershing

The path to the new tank had been pocked by bureaucratic infighting: By the fall of 1943, the Armored Command was in favor of a vehicle mounting the 90mm gun, but preferred that the Sherman tank be upgunned to this standard since there was little chance of the new T25 or T26 being fielded in time for the upcoming invasion of France. Ordnance asserted that the M4 would be overloaded by the approximately 9,200lbs (4,200kg) added by a 90mm gun turret, and instead preferred production of one of the new 90mm tanks. Major General Alvan Gillem, who had assumed command of the Armored Force on 11 May 1943, thought the 90mm gun turret would only weigh 4,000lbs (1,800kg) more than the 76mm gun turret, and his figure is probably more accurate than the Ordnance Department's. AGF had no objection to a new tank, but disagreed with both on the 90mm gun issue.Hunnicutt, Sherman 212. Baily 86-7, 95, 122, 126. Mayo, 328-9, 338. Zaloga, Armored Thunderbolt, 112-3, 123-4.

AGF's McNair was hesitant to approve the 90mm gun since he believed the new weapon would encourage tankers to seek out duels with enemy armor and thereby distract them from their primary mission of engaging targets that were more vulnerable to tanks.Baily, 94-5. Zaloga, Armored Thunderbolt, 123-4. Armored Force field manuals, on the other hand, had consistently listed enemy tanks as potential targets for friendly medium tanks. In March 1942, FM 17-10 Armored Force Field Manual: Tactics and Technique directed, "Medium tanks...protect the light tanks against the attack of hostile tanks. When the enemy is composed of mechanized troops, a large medium tank component, if available, is held in the reserve." Referring to GHQ tank battalions, this manual advised, "[Medium tanks] are used offensively against hostile tanks...During the course of an attack GHQ tank units may be used offensively, in conjunction with other available antitank measures, to attack hostile mechanized forces threatening to break up or disorganize the main effort...GHQ tank units attached to army corps or divisions may be used in large numbers to break up hostile mechanized formations." The September 1942 edition of FM 17-33 Armored Force Field Manual: The Armored Battalion, Light and Medium included the "support by fire [of] the advance of light tanks, other medium tanks, or infantry in tank versus tank action" among the uses of medium tanks. The December 1944 revision of FM 17-33 asserted that medium tanks may be used "[w]hen necessary, against enemy tanks", and indeed one purpose specifically assigned to 76mm gun medium tanks was to "reinforce the antitank defense of a supported infantry unit."FM 17-10, 91, 341, 345-6. FM 17-33 Sep 1942, 4. FM 17-33 Dec 1944, 9. Technical manuals for the Sherman also evinced the intention of taking on enemy armor with medium tanks. TM 9-731B Medium Tank M4A2 from January 1943 suggested that fully 40% of the 75mm ammunition loadout should be armor-piercing.TM 9-731B Similarly, TM 9-731A Medium Tanks M4 and M4A1 from December 1943 alleged that the tanks' armament was "employed chiefly against enemy tanks and other ground objectives;" later, TM 9-759 Tank, Medium M4A3 from September 1944 echoed this.TM 9-731A, 351. TM 9-759 Dec 1944, 380, 400. Finally, the reticle etchings in tank gun sighting telescopes were graduated based on armor-piercing projectiles.

Periscope M4 with telescope M38

Another factor muddling the 90mm tank gun adoption was the absence of consensus among field commanders regarding its necessity. This lack of unanimity was evident when queries were issued in late 1943 about which versions of the T20 series were preferable. The North African Theater of Operations, commanded at the time by General Eisenhower and containing the only two US armored divisions that had yet seen action, wanted the 76mm gun versions only and thought that the 90mm gun versions would be too heavy and stow too few main gun rounds. The European Theater of Operations replied that they would desire the 76mm gun versions, but would like work to continue on the 90mm gun versions.Baily, 92-4. Zaloga, Armored Thunderbolt, 122-3. The T26E1 only stowed forty-two 90mm rounds, far less than the requirement of seventy set down by the European Theater. Among other workarounds, wet stowage was dropped in favor of additional space for the 90mm rounds. See Hunnicutt, Pershing, 116. As late as February 1943 even the Tank Destroyers had no interest in a 90mm GMC since it was thought the 3"/76mm guns were sufficiently powerful.Baily, 72. As well the Armored Board, when asked by AGF about putting the T25 or T26 into production, replied on 6 April 1944 that it desired 640 T25s with 105mm howitzers, 2,400 T25s with 76mm guns, and 4,560 T25s with 75mm guns.Baily, 121. In contrast, the Fifth US Army, after becoming mired in tough fighting in Italy, requested in March 1944 that of all its 75mm gun tanks and M10 GMCs be replaced with 76mm tanks and 90mm GMCs as soon as possible.Fifth Army soon modified its request for total replacement of its M10s by 90mm GMCs, which had yet to be standardized, for 2 battalions' worth, with allocation of subsequent 90mm GMCs pending results of testing by that army. Moran, <https://worldoftanks.com/en/news/chieftain/​The_Chieftains_Hatch_Undergunned_Italy/>. The 755th Tank Battalion was among units in Italy that became disillusioned with the 75mm gun, writing in its after action report for June 1944 that, "The 75mm gun now mounted on the M-4 tank cannot successfully combat the German Self-Propelled guns, Mark IV [Pz.Kpfw.IV], Mark V [Pz.Kpfw.Panther], and Mark VI [Pz.Kpfw. Tiger] tanks."Layne, "BATTLE REPORT for June 1944," 10. The European Theater similarly changed its mind shortly before the Normandy invasion and requested that production of 75mm and 76mm gun tanks be halted in favor of 90mm gun and 105mm howitzer tanks, but in a ratio of one gun tank to three howitzer tanks.Hunnicutt, Pershing, 195. Baily, 102. Mayo, 330-1. Still, in May 1944 Eisenhower, who in February that year had become the Supreme Allied Commander of the Allied Expeditionary Force, told the US War Department that converting Tank Destroyer battalions in Europe to the newly-standardized 90mm GMC M36 was not desired.Baily, 71-2, 90, 102. Gill, 40-1.

90mm gun motor carriage M36

Initial resistance to the 90mm gun was partly due to faulty test data. Ordnance tests claimed the 3" and 76mm weapons could penetrate a Pz.Kpfw.Tiger Ausführung (Ausf.) E frontally to 2,000 yards (1,800m).Gabel, Seek, Strike, and Destroy, 52. Actual encounters with enemy fortifications and heavier German tanks like the Tiger and Panther would prove that these tests and the line of thinking they engendered were sadly incorrect, and the Panther would be relatively common among enemy tanks throughout the western European campaign.To compare the Panther's commonality in the theater with that of Germany's most-produced tank, the Pz.Kpfw.IV: In the Western Front on 10 June 1944 there were 758 Pz.Kpfw.IV and 655 Pz.Kpfw.Panther available. On 15 December 1944 there were 391 Pz.Kpfw.IV operational out of 503 available (78%) versus 336 out of 471 Pz.Kpfw.Panther (71%). On 15 March 1945 there were 19 Pz.Kpfw.IV operational out of 59 available (32%) versus 49 out of 152 Pz.Kpfw.Panther (32%). Jentz, ed., Panzer Truppen, 2: 177, 202, 248. After July 1944 firing trials at Isigny, France, demonstrated the difficulty the US 76mm and 3" guns would have with the Panther's frontal armor, Eisenhower complained, "Ordnance told me this 76 would take care of anything the Germans had. Now I find you can't knock out a damn thing with it." That same month the Army again briefly considered mounting the Pershing's 90mm gun turret on the Sherman, but since the M26 was anticipated to enter mass production in the months it would have taken to build up a useful number of 90mm Shermans, it was instead decided to concentrate on the new tank.Johnson, Fast Tanks and Heavy Bombers, 194. Ross, 288. Yeide, The Tank Killers, 135. Napier, 421. Fletcher, The Universal Tank, 102. Mayo, 331. Hunnicutt, Sherman, 212. Zaloga, Armored Thunderbolt, 128-9, 180. The British were also dissatisfied with the performance of the 3" gun versus "modern tanks at fighting ranges;" see Knight, A30 Challenger Tank, 77. Reports from Europe detailing the inefficacy of current guns when dealing with heavy enemy armor spurred a crash program to expedite the design and distribution of hypervelocity armor-piercing (HVAP) ammunition for the 3"/76mm guns, the development of which had been hitherto ignored due to the notion that the existing armor-piercing shells were sufficient. Unfortunately the HVAP shot's penetrating core was made of tungsten, which had to be imported from China and husbanded for machine tools, ensuring that up to March 1945 the new ammunition was scarce to the point of providing only two rounds per gun per month in Europe.Green, Thomson, and Roots, 372-3. Baily, 109. Mayo, 336. With such experience behind it, by January 1945 the European Theater's preferred ratio of gun to howitzer tanks flipped to four gun tanks to each howitzer tank.Mayo, 330-1.

However, even 90mm gun tanks would have struggled against the Panther's upper front hull for all of 1944: firing trials that December by the 703d Tank Destroyer Battalion using the M36 only produced a penetration about half the time from a frighteningly close range of 150-300 yards (140-275m). The Panther's glacis would remain largely invulnerable to American guns until the 90mm HVAP T30E16 and 90mm armor-piercing T33 rounds arrived in Europe in early 1945. The T30E16 shot could get through the Panther's upper front hull from 450 yards (410m) away; it could even get through the upper front hull of the Pz.Kpfw.Tiger Ausf.B, but only at a range of 100 yards (90m). The T33, while unable to defeat the Panther's gun shield, could penetrate its glacis plate from a more comfortable 1,100 yards (1,000m).Baily, 106-7, 109-10. Hunnicutt, Pershing, 120-1. Zaloga, Armored Thunderbolt, 218-9. Armor-piercing Ammunition for Gun, 90-mm, M3, 1, 6. Zaloga says the T30E16 arrived in Europe in January 1945, but Baily says neither type appeared there until March. Hunnicutt says small quantities of both were available for the 20 Zebra Mission Pershings. With more effective guns and ammunition becoming available, AGF's earlier prediction about powerful gun tanks seeking out enemy armor rang true. Indeed, the pilot of the long-gunned T26E4 "Super Pershing" that was sent to Europe in March 1945 was hoping to encounter a Tiger Ausf.B.Hunnicutt, Pershing, 28, 195. Baily, 138. Cooper, 231, 234. Hunnicutt claims that such an encounter never occurred, but the gunner of the T26E4 at least implies that a Tiger Ausf.B was destroyed. See Irwin, 82-3, 138. Zaloga, Armored Thunderbolt, 290, asserts that the T26E4 potentially knocked out two Tigers, but does not specify Ausführung for either.

Medium tank T26E4 Pershing

The seeming impotence of the 75mm and 76mm guns against heavier German tanks soured US tankers' opinion of the Sherman,General Board, European Theater, Tank Gunnery, 26. For examples, see White's report and "Armored Force, Command, and Center," 88. but Great Britain would be able to mount a more potent armor-piercing weapon. In late 1943, it was discovered that the 17 pounder antitank gun could be modified to fit in the 75mm gun turret of M4 and M4A4 tanks with hydraulic turret traverse and the gun mount M34A1, and conversions using the 17 pounder Mark IV or VII started that December. The British had been trying to get their 17 pounder into a tank with their Challenger program, but its stopgap nature and delays due to redesigns ensured that the Sherman would be the most common 17 pounder tank in their inventory.Hayward, 14-6. Knight, A30 Challenger Tank, 27-8, 37. Fletcher, The Universal Tank, 85. Hunnicutt, Sherman, 304. Smithers, Rude Mechanicals, 177-8.

These tanks, designated Sherman IC or VC but also known as Fireflies, were not without problems, however. Fitting the hefty gun into the 75mm gun turret resulted in a cramped fighting compartment akin to what the US Armored Force had rejected in the Ordnance Department's original 76mm gun attempt, and the assistant driver was deleted in favor of more stowage room for the 17 pounder's large ammunition. Also, the 17 pounder had similar target obscuration problems as the US 76mm gun, had accuracy issues especially with armor-piercing discarding sabot (APDS) rounds, and it was initially issued without high-explosive ammunition. The Panther's upper front hull plate remained relatively impervious to the gun with APCBC ammunition, and caused even APDS ammunition to struggle.Buckley, 111, 118, 130-1, 162. Baily, 108. US tankers interviewed after the war unanimously desired a bow machine gun. See General Board, European Theater, Tank Gunnery, 33. Knight, A30 Challenger Tank, 48, 65, 68. Moran, <https://worldoftanks.com/en/news/chieftain/​The_Chieftains_Hatch_Firefly/>. Moran, <https://worldoftanks.com/en/news/chieftain/​The_Chieftains_Hatch_Firefly2/>. Taylor, Firing Now!, 21. 17 pounder HE shells did enter service, but there are British reports from as late as May 1945 calling them "unsatisfactory." Hayward, 16-7, 36, 40-1, 56.

Unlike the US Army, the British did not hesitate to send these tanks into action despite their disadvantages and novelty: around 200 Fireflies were available at the beginning of June 1944, enough for each cruiser tank regiment to have twelve 17 pounder tanks, and they started landing with the second wave at Normandy. Once it was obvious that the Fireflies had better armor-piercing performance than the US 76mm guns, the US Army became interested and requested a number in August 1944. A shortage of the proper type of Sherman tank required for the conversions shelved the idea until March 1945, when the US was finally able to acquire eighty Fireflies, including some based on the M4A3. By then, 90mm gun tanks had become available, and this combined with a shortage of 17 pounder ammunition (especially high-explosive) to end the American Firefly program.Hayward, 32-5, 59. Napier, 83. Buckley, 16-8, 169-73. Hayward, <http://freespace.virgin.net/shermanic.firefly/usnew.html>. Zaloga, Armored Thunderbolt, 180-1, 276-7. Mayo, 336. A few Fireflies were acquired by US forces, however, and at least one of these tanks participated in hostilities: the 755th Tank Battalion reported that while in the Po Valley between 19 and 22 April 1945 it "drew fifteen (15) 17 pounder M4 tanks, seventeen (17) M4A3's and seventeen M4's. Seventeen (17) M-24 Light tanks were drawn on 20 and 21 April, and assigned to D company."See Fowler, "Report of action during period 11 April 1945 to 2 May 1945," 1; and Fowler, "Battle Report for April 1945," 2. On 27 April a single Firefly was attached to a platoon of M24s from Company D, and this force assisted tanks from Company B and infantry from the 133rd Infantry Regiment in engaging enemy self-propelled guns, knocking out three Pz.Kpfw.IV, and taking 700-1,000 prisoners.Fowler, "Report of action during period 11 April 1945 to 2 May 1945," 3; and Fowler, "Battle Report for April 1945," 3.

Irrespective of gun or armor deficits between American tanks and heavier German vehicles like the Panther, the experience level and quality of tank crews and the tactical situation in which they found themselves played a great role in determining the outcome of encounters. For example, casualties incurred by separate tank battalions were most numerous in the units' earliest days in combat. The surviving men quickly learned from these first actions and became savvier and more lethal as the war progressed, with the casualty rate consequently decreasing.Yeide, Steel Victory, 17-8. Data culled from battlefield studies also suggested that the side that saw--and therefore fired upon--the enemy first had a probability of success that outweighed any technical superiority in equipment; postwar experiments agreed with this conclusion. US Army tankers interviewed just after the war "emphasized the urgency of being able to fire the first accurate round." (Emphasis in original.) The defender would typically have advantages in both spotting an attacker first and initiating an engagement at the time and place of his own choosing, and the Axis was of course defending for most of the campaign.See Hardison, 29-30; and Gee, 26-7. Sorely, ed., Press On!, I: 38-40. Longman, para. 8. Quoted in General Board, European Theater, Tank Gunnery, 27. Zaloga, Armored Thunderbolt, 229-32. Rowland, 178-84, quantifies the effect of surprise in a number of World War II armored engagements. For a practical illustration in which the Germans took to the offensive, September 1944 attacks against the 4th Armored Division around Arracourt were foiled despite the Germans having over 200 Panthers available. Thicker armor and more powerful guns were no guarantor of battlefield success.Zaloga, Patton versus the Panzers, 188-94.

One technological advantage possessed over enemy tanks was gyrostabilized guns on the medium tanks M3 and M4, and light tanks M3, M5, and M24. The requirement for the stabilizer system was to be able to decrease deviations to ±⅓° for ±2.5° movements of the vehicle at 1.5Hz. The finished product, overseen by Westinghouse Electric and Manufacturing Company engineer Clinton R. Hanna, exceeded this requirement, managing to lower the deviation for vehicle movements of ±2.5° at 1.5Hz to below ±⅛°. The financial impact imposed by the device was under 1.4-2.4% of the 1943 price of a Sherman tank.Summers, 10-1, 23. Summers, 11, says the stabilizers cost "less than $1,000." Thomson and Mayo, 256, list 1943 prices for the Sherman ranging from a low of $42,400 at the Detroit Tank Arsenal to a high of $70,000 at the Federal Machine and Welder Company.

Medium tank M4A2 Sherman

FM 17-12 Armored Force Field Manual: Tank Gunnery from April 1943 asserted that the system "...merely tends to keep the gun where it has been laid; that is, it eliminates extremely jerky movements caused by the movement of the tank. Even with a stabilizer, the gun does not hold constantly on the target." Nonetheless, coaxial machine gun accuracy was improved, and although the FM admonished that firing the main gun on the move was typically to be done "only in an emergency," "expert crews" were able to effectively fire from moving tanks at ranges of up to 600 yards (550m). (Emphases in original.)FM 17-12, 4, 34, 46. The British were more liberal, noting, "Although the accuracy of fire from a moving vehicle even when fitted with the gyro-stabilizer can never be equal to that from a stationary one, it will, nevertheless, be necessary to fire on the move during the final assault or in a surprise encounter during movement"; British gunners were trained to use the machine gun out to 800 yards (730m) while moving, high-explosive shells to 1,000 yards (910m), and armor-piercing projectiles to 600 yards (550m).Sherman Tanks 75 mm. M3 Gun and Coaxial .30" Browning Machine Gun Armament Training Pamphlet, 204-6. German tankers, on the other hand, were instructed to fire from the halt.Jentz, ed., Panzer Truppen, 1: 76. Jentz, Tiger I & II: Combat Tactics, 32. Jentz, Tank Combat in North Africa, 59. Fletcher, ed., Tiger!, 43. Forczyk, 18. This of course was not adhered to during every engagement: see, e.g., Lawrence, 459, 518.

Drawbacks to the device existed, and included radio interference, depletion of the tank's batteries, and the obligation to set aside time devoted to training and maintenance. Well-trained units, for example Lieutenant Colonel Creighton Abrams's 37th Tank Battalion, 4th Armored Division, were able to reap the benefits conferred by the stabilizers. However, until late in the war many US units still preferred to fire from the halt to ensure maximum accuracy and therefore simply disconnected the devices.Sorely, Thunderbolt, 63. Hunnicutt, Sherman, 215. Hunnicutt, Stuart, 142. Zaloga, Armored Thunderbolt, 39. Green, Thomson, and Roots, 343. General Board, European Theater, Tank Gunnery, 54. Cameron, Mobility, Shock, and Firepower, 392-3, 463. The stabilizers in many Soviet Lend-Lease tanks shared a similar fate due to their novelty and maintenance requirements. See Kinnear and Sewell, Soviet T-54 Main Battle Tank, 86.

Foreign militaries and engineers took notice of the equipment. Most concretely, the Canadian cruiser tank Ram II featured the Westinghouse stabilizer for its 6 pounder gun.The Ram would not see combat as a gun tank, however. Lucy, 69-71. Blue, 33, 47. Additionally, Soviet tests involving Lend-Lease M4A2 Shermans showed that firing on the move with the stabilizer could result in a hit rate of 87% with a rate of fire of 5.17 rounds per minute, versus a hit rate of 47% at 3.87 rounds per minute without the stabilizer. The M4A2(76)W performed just as well during Red Army tests, with accuracy compared to unstabilized fire increasing with speed from a factor of two at 15kph (9.3mph) to a five- to six-fold improvement at 25kph (16mph).Samsonov, Sherman Tanks of the Red Army, 35-6, 45. Although official requests for work on tank gun gyrostabilizers had existed in the Soviet Union since at least 1930, experience with this equipment spurred on that country's development which culminated in 1955 with the adoption of the STP-1 Gorizont vertical stabilizer system in the T-54A.Samsonov, <https://www.tankarchives.ca/2014/03/soviet-stabilizers.html>. Kinnear and Sewell, Soviet T-54 Main Battle Tank, 23, 86-9. Hull, Markov, and Zaloga, 24. Similarly, when interviewed by British and US Army personnel in early June 1945, Dr. Gerd Stieler von Heydekampf, who in December 1943 had succeeded Dr. Ferdinand Porsche as head of Germany's Panzerkomission, attested that American tank gun stabilizers had been impressive enough to send Germany down the path of developing its own.Estes, German Heavy Fighting Vehicles, 154.

Another benefit possessed by some later US tanks was wet ammunition stowage, introduced with other improvements to the medium tank design in January 1944 and included with the M24 light tank when it entered production that April. Once committed to battle, the M4 had earned a reputation for easily catching fire when hit.On the Sherman's reputation for flammability, see, e.g., Buckley, 127; Courage, 71; Makos, 127; Napier, 80-1; Yeide, Steel Victory, 14. It was determined that ammunition fires were the main culprit, and although the crews themselves may have contributed to this risk by improperly stowing or carrying extra main gun ammunition, work was done to try to correct the tank's flammability. "Armored Force, Command, and Center," 96-7. Ross, 249. Hayward, 17. Yeide, Steel Victory, 21. Buckley, 128. Napier, 98. Elson, 152. Neiman and Estes, 94. Liddell Hart, The Tanks, 2: 248. For the Normandy invasion, the crews of some US amphibious duplex drive medium tanks carried so much extra ammunition that the freeboard of their vehicles was reduced from the usual 30-36" (76-91cm) to as little as 9" (23cm). See Napier, 11, 47. At least some German, Soviet, and Italian crews also took part in this practice. See Green and Green, 77; Spielberger, Doyle, and Jentz, 66; Loza, Fighting for the Soviet Motherland, 157, 160; Bryukhov, 107; and Riccio, 135. The British had also learned this lesson, although it had been practiced since World War I. See Knight, A15 Cruiser Mk.VI Crusader Tank, 32-4, 49; Glanfield, 141; Courage, 158. The resulting wet ammunition stowage layout moved main gun ammunition to below the sponson line and stored it in double-walled water-lined boxes. Wet stowage decreased the incidence of fires from 60-80% in knocked-out dry stowage tanks to 10-15% in tanks with the new arrangement.Zaloga, Armored Thunderbolt, 118. Buckley, 128, agrees with the 15% burn rate for wet stowage Shermans. Counterintuitively, a British survey found that the Sherman did not significantly differ from the Cromwell, Challenger, Churchill, or Stuart in regards to percentage of crewmen burn casualties. All those vehicles incurred about 25% of their casualties due to burns. The total casualties per knocked out tank was also similar between the different types in the survey. See Fletcher, The Universal Tank, 115-6. The practice was apparently discontinued shortly after the war, however: the 6 February 1951 edition of the M24's technical manual notes that, "The use of any fluids (water, antifreeze compound, or ammudamp) in ammunition box cans has been discontinued."TM 9-729 Light Tank M24, 43. The British later adopted a pressurized wet stowage system for the propellant bins in the Chieftain tank and early marks of the Challenger tank.The Challenger in this case is the 1983 main battle tank that recycled the name of the World War II vehicle. Hilmes, 79-80. Griffin, Chieftain, 55. Griffin, Challenger, I: 18.

Early German successes in Europe finally convinced the Field Artillery that horse-drawn guns were obsolete, but many still harbored contrary opinions about self-propelled mounts, preferring instead tractor-towed field pieces. Nonetheless, in June 1940 the Ordnance Department began work on a fully-tracked self-propelled 75mm gun using the light tank as a basis. Devers instead proposed a concept developed with Colonel Edward H. Brooks for mounting a 105mm howitzer on a carriage based on medium tank components. A turret and the vehicle roof were eliminated, the armor was thinned to lessen weight and increase speed, and the howitzer was affixed in a limited-traverse mount to the driver's right. The vehicle was standardized as the 105mm howitzer motor carriage (HMC) M7. The first vehicles were finished in April 1942, after which they were nicknamed Priest due to the pulpit-like machine gun mount in the front right corner. Thus in contrast to earlier towed or half-track-based ordnance, Army armored units now possessed artillery support that could keep up with tanks cross-country, and in battle self-propelled artillery would suffer less than half the crew casualties per knocked-out tube compared to towed pieces.Dastrup, King of Battle, 205-6, 212. Green, Thomson, and Roots, 314-5. Adams, 74-5. Wheeler, 157-8. Hunnicutt, Sherman, 333-5. Dupuy, 93-4.

105mm howitzer motor carriage M7

The 105mm howitzer was not the heaviest weapon that was mechanized. In the spring of 1941 the Ordnance Department commenced a study on designing a carriage for a 155mm gun with automotive assemblies from the medium tank M3, but both AGF and the artillery were apathetic. Work progressed on the design, and beginning in September 1942 one hundred of the vehicles were delivered as the 155mm GMC M12. Modifications to improve the internal stowage and engine exhaust as well as to correct engine vapor lock issues were required, and beginning in May 1944 seventy-four M12s were rebuilt with the necessary changes. Despite their limited numbers, these few vehicles provided valuable service in Europe firing both direct and indirect missions.Hunnicutt, Sherman, 348-52. Mayo, 300-1. Green, Thomson, and Roots, 316-7. Doyle, M40 Gun Motor Carriage and M43 Howitzer Motor Carriage, 4.

155mm gun motor carriage M12

Armor also saw action in the Pacific Theater with both the Army and Marines. Indeed, the first American-crewed tanks to engage enemy ground forces in World War II were a platoon of Army M3 Stuarts from Company B, 192d Tank Battalion (Light). As they were advancing to contact a Japanese landing force near Agoo in the Philippines on 22 December 1941, the group encountered hostile infantry and were subsequently repulsed by a roadblock that included Type 95 light tanks from the Imperial Japanese Army's 4th Tank Regiment.Hunnicutt, Stuart, 395. Salecker, 1-5. Zaloga, Armored Thunderbolt, 301-2. Yeide, The Infantry's Armor, 18-9.

Light tank M3 Stuart

The USMC began World War II with a tank battalion intended for infantry support in each division, but tank-infantry cooperation was dismal in early Marine operations, and it was not until after difficulties at Guadalcanal and Tarawa that training in this area intensified and matured.Alexander, 189-91. Gilbert, Marine Tank Battles in the Pacific, 141. Estes, Marines Under Armor, 104. Combat experience showed the Marines that their light tanks were vulnerable, underarmed, and underpowered for moving through the thick Pacific jungles, so they made the move to the Sherman medium tank in time for the battle of Tarawa in November 1943.Alexander, 185, 194. Estes, Marines Under Armor, 53-4, 71. Gilbert, Marine Tank Battles in the Pacific, 78. Green, War Stories of the Tankers, 93-4. Usage of the heavier medium tanks forced the design of more robust landing craft such as the landing ship, tank (LST), and landing craft, mechanized (LCM), since the Sherman's 35-ton (32-metric ton) bulk could not be handled by earlier vessels.Alexander, 194-5. Gilbert, Marine Tank Battles in the Pacific, 82. Croizat, 31. The Army had standardized on the gasoline-fueled M4A3, meaning that the Marines could more quickly obtain numbers of the diesel-powered M4A2.Estes, Marines Under Armor, 56. The Corps was forced to convert to 75mm gun M4A3s, though, once M4A2 production switched to the M4A2(76)W in mid-1944.Estes, Marines Under Armor, 88-9. The Marines relished the 75mm gun's more potent high-explosive shell, and preferred that capability over the increased armor penetration conferred by the 76mm gun. In any case, the Sherman was the most powerful tank that fought in the Pacific Theater, and it proved devastating against Japanese armor even without the 76mm gun.Japanese tanks were not helped by their usage in the field. Contrary to their armored doctrine, Japanese tanks were typically used in piecemeal counterattacks or as static artillery pieces. See "Japanese Tank and Antitank Warfare," 86-103. Eventually the Army, concentrating on the new M26, totally ceased production and support of the 75mm gun tanks, so in 1945 the Marines decided to standardize on the still-in-production M4A3(105); however, budgetary shortfalls ensured that not all Marine Shermans were armed with the 105mm howitzer even by 1950.Estes, Marines Under Armor, 90, 111, 117. Gilbert, Marine Corps Tank Battles in Korea, 5, 269.

Medium tank M4A2 Sherman

An innovation in infantry vehicles that was perfectly suited to the Pacific Campaign was the tracked landing vehicle (LVT). The first LVTs were modified versions of Donald Roebling's Alligator, which had been used as a swamp rescue vehicle in Florida's Everglades, and a battalion of amphibian tractors equipped each Marine division at the start of World War II.Alexander, 189. Donald was the great-grandson of John Roebling, designer of the Brooklyn Bridge, and was initially hesitant to design a military version of his vehicle. See Croizat, 31-2. At first the LVT was seen simply as an efficient mechanism of transporting supplies inland from ships until wheeled supply vehicles could be landed, but it was not long until a more direct military function as an assault craft was envisioned, and LVTs premiered in this role with the Marines at Tarawa and the Army at Makin in November 1943.Alexander, 185, 191. Estes, Marines Under Armor, 70-1. Gilbert, Marine Tank Battles in the Pacific, 78. Yeide, The Infantry's Armor, 97-8. Salecker, 93. Crowl and Love, 47-8. Croizat, 86, 97-8. Research, Investigation and Experimentation in the Field of Amphibian Vehicles, 51, 55. The amphibious tractor battalions were organized along the lines of a motor transport battalion. See Croizat, 40-1. Confidence in the vehicles was probably not inspired by FM 17-34, which asserted on p.2 that the LVTs were "relatively seaworthy." LVTs initially used in assault landings were unarmored or fitted with applique armor plates, and the position of the engines in the rear of the vehicle made for a tension-filled dismount over the tall sides. The LVT3 and LVT4 remedied that problem and greatly eased cargo handling by repositioning the engines and adding a rear loading ramp.

LVT4

Armored amphibians were also developed to give the assault craft direct fire support during the landing and immediately after. Although referred to as amphibian tanks, their thin armor was a hindrance in combat, especially when acting as "land tanks." The amphibian tanks were to lead the assault, firing on the beach defenses as they approached, then once ashore support the infantry or engage in indirect fire if needed. The armament of the armored amphibians started out as a small 37mm gun on the LVT(A)1, but advanced to a 75mm howitzer on the LVT(A)4. Armored amphibians were not used in the European Theater, but cargo LVTs were used by the US and British during a few river crossings and by the British and Canadians during the invasion of the Scheldt estuary and occupied islands around Antwerp.The Rhine was one such river crossed by the British with the help of amphibian tractors. General Board, European Theater, Armored Special Equipment, 23-4. Yeide, Steel Victory, 233, 244. Yeide, The Infantry's Armor, 240, 243. Fletcher, The Universal Tank, 106. Croizat, 190, 192-7. Liddell Hart, The Tanks, 2: 329, 418-20, 422-3, 428-9, 434, 436-7, 440, 442-4. Macksey, Armoured Crusader, 308-10, 313-5.

LVT(A)1

The British practice of dubbing vehicles and weapons with nicknames was eventually semi-officially accepted by the US Army. On 24 November 1944 Ordnance Department Executive Assistant Colonel W.A. Weaver issued a memo listing names for vehicles and weapons that had "been adopted and will be used in public information release." Though not to be used in official or technical correspondence, the nicknames provided included General Stuart for the light tank M5, General Chaffee for the light tank M24, General Sherman for the medium tank M4, General Jackson for the 90mm GMC M36, Priest for the 105mm HMC M7, General Scott for the 75mm HMC M8, and Hellcat for the 76mm GMC M18. In contrast to Churchill, the Ordnance Department was apparently unafraid of any confusion the use of "General" might cause.Moran, <https://worldoftanks.com/en/news/chieftain/chieftains-hatch-whats-name/>.

75mm howitzer motor carriage M8

Industrially, the United States was unmatched during World War II. Railway manufacturers were initially tapped for tank production, but the mass-production expertise of automotive companies was then harnessed in their own plants as well as specially-built tank factories. Having gotten past early shortages in tank engines, armor steel, and final drive and transmission machine tools, over 49,000 Sherman tanks were produced from 1942 to 1945,Thomson and Mayo, 244-50. Hunnicutt, Sherman, 525. along with almost 14,000 M3 and almost 9,000 M5 light tanks.Hunnicutt, Stuart, 464. All of the engines and almost all of the transmissions for tank-based vehicles assembled in Canada were imported from US factories.Law, 51-2. Besides a few kept for unit training, the entire production runs of the T16 carrier, M5 and M9A1 half-tracks, and Staghound armored car were allocated to foreign countries through Lend-Lease; likewise, the US was able to spare to its Allies over 11,500 light and 26,600 medium tanks.Hunnicutt, Bradley, 11. Hunnicutt, Half-Track, 52, 199. Hunnicutt, Armored Car, 82, 91. Crismon, U.S. Military Wheeled Vehicles, 75. Hunnicutt, Stuart, 464. Hunnicutt, Sherman, 526. Germany, on the other hand, produced just over 25,000 tanks of all types from 1938 to 1945, and the British were outproduced in tanks by almost three-and-a-half times from 1940 to 1945.Chamberlain and Doyle, 261-3. Note that due to an offer of increased numbers of American Lend-Lease tanks, British tank production was intentionally throttled in favor of locomotive production. See Coombs, 41, 47-8, 55, 102, 109, 121-4; and Knight, A34 Comet Tank, 4-6, 8-9, 11-3, 16-7. From 1942-1944, the US churned out more tanks and self-propelled artillery than any other nation; when the time period is expanded to from 1939 to August 1945, including the years before the US entered the conflict, only the USSR eclipsed the American total in tanks and self-propelled guns, and only by 3.3%.Mark Harrison, "The economics of World War II: an overview," in The economics of World War II, Harrison, ed., 15-7.

Medium armored car T17E1 Staghound I

This cornucopia of machinery allowed the US Army to mechanize itself to an enviable degree. For example, US armored divisions fielded enough armored half-tracks to transport all of their infantry, and all of the artillery in the armored divisions was self-propelled. Contrast this to a Panzer-division, which typically mounted only one-fourth to half its infantry in Sonderkraftfahrzeug (Sd.Kfz.) 251 armored half-tracks and which used mostly towed artillery throughout the war. Indeed, under 12% of German Panzergrenadier battalions rode in the Sd.Kfz.251 even when these vehicles were at their most prevalent.Ogorkiewicz, Armoured Forces, 77-9, 90. Bellanger, 227, 300, 367. Culver and Feist, 8, 20. Haworth, 14. Simpkin, Mechanized Infantry, 22.

Half-track personnel carrier M3A1

These staggering figures were helped by the conservation of valuable materials achieved by the Ordnance Department, and armored vehicles played a large role in this process. Low-alloy armors saved valuable nickel, chromium, and vanadium without compromising protection; individual parts were studied to trim unneeded material "fat" from their designs.Green, Thomson, and Roots, 484-5. Until work on synthetics alleviated a rubber shortage, the required runflat distance for combat tires was reduced from 75 to 40 miles (120 to 64km) in the interests of saving rubber from the tires' sidewalls.Green, Thomson, and Roots, 501.

One area where conservation was de-emphasized was in the makeup of tank tracks. Tracks with synthetic rubber shoes were not up to the task of handling the weight of medium tanks. So in the constant quest to save rubber, steel-shoed tracks were investigated to replace those with rubber shoes. The deleterious effect of the steel tracks on the tanks' running gear, however, led Ordnance to propose that only rubber-tracked tanks be sent overseas. But once so equipped, the troops in Italy requested steel tracks be sent again since they were more durable in the rocky terrain there. A rubber-backed steel track was finally developed as a compromise, and Ordnance was later authorized to issue whatever type of track would be suitable for specific operations or terrain.Green, Thomson, and Roots, 306-8, 502. Brockman et al., 62-3; included on p.63 is a survey of tank, tank recovery vehicle, and howitzer motor carriage crews in Italy who overwhelmingly preferred rubber tracks despite their decreased life compared to steel tracks.

Despite the great efforts made in war production, a drastic tank supply crisis occurred in late 1944. Production requirements were lowered in late 1942, and such a great tank production potential had been created that in the last quarter of 1943, even after four tank plants had already ceased operating, production output was less than half of available plant capacity. More factories were therefore shut down. Hugh Weeks, the Head of Programmes and Planning at the British Ministry of Production, foresaw a coming danger as early as February 1944 when he noted the US was asserting that an artificially high 96% of the medium tanks it had accepted since it entered the war were still available; this contrasted to 54% for the British. As Weeks feared, the planned slowdown in medium tank production intersected with the Army's realization that many of the older tanks it had been counting as available were, in fact, not serviceable. In addition, the fighting in France used more tanks than the Army had anticipated. Theater commanders' desires for a replacement factor of 20% for medium tanks were ignored during the invasion's planning stages, and the War Department instead authorized a fantastically low 7% replacement factor and a reserve of 17.5% for the operation. For comparison, in May 1944 the British 21st Army Group requested a tank wastage rate of 25% per month for the first three months post-invasion, and that country sent a medium tank reserve of a full 50%. Calculations released in mid-November 1944 showed that the British had amassed 6,434 reserve medium/cruiser tanks versus America's reserve stocks of 3,759 machines. Although slowly increased throughout the year, War Department revisions to the replacement factor were not reflective of actual battlefield experience until December 1944. These circumstances led to a dearth of medium tanks actually in the field, and reopening the shuttered assembly lines would be a time-consuming and expensive process. Production from the remaining manufacturers was increased and rebuild programs for older tanks were instituted, and in an effort to more speedily build numbers up the US canceled Lend-Lease tank orders to Britain for November and December 1944--recouping 3,469 vehicles--and halting further tank shipments until April 1945. Germany's December 1944 Unternehmen Herbstnebel offensive in the Ardennes added yet more tension, but by March 1945 the crisis period had passed and production was once again reduced.Fletcher, The Universal Tank, 96, 102-3. Zaloga, Armored Thunderbolt, 180-1. Napier, 72, 409. Thomson and Mayo, 256-9. Coombs, 125-7. Knight, A34 Comet Tank, 51, 93, 100, 139-40, 144. Ruppenthal, I: 522-3; and Ruppenthal, II: 236-41. Brockman et al., 47-8. The German offensive that reporter Larry Newman would dub the Battle of the Bulge was to be called Unternehmen Wacht am Rhein, but Hitler switched its name in December 1944. See Caddick-Adams, 110, 655-6.

Even after the tanks were assembled, a large delay in delivery to the troops was induced by the geography of the war: shipment of the vehicles across either the Atlantic or Pacific Oceans was necessary to reach their final destinations. Studies in early 1945 showed that it normally took eighty-seven days for supplies to arrive in European units from New York. Peregrination across the broader Pacific Ocean to ports in Australia or New Guinea could double the transit time. Once the tanks arrived at the correct port, around fifty working hours were then required for tasks including the removal of rustproofing and stowage of crated equipment before the tanks could be actually be issued.Millett, 49, 58. Brockman et al., 32-3, 88, 93-4, 98.

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The Atomic Age: Retaining Relevance

Battlefield research conducted upon the end of World War II caused the tank's place in antitank defense to be reevaluated. Importantly, AGF's stance that friendly tanks were not to seek out enemy armor was debunked: the General Board of the European Theater explicitly stated in its postwar studies that "[t]he European campaign demonstrated that tanks fight tanks," and also that the "current thought is that the medium tank is the best anti-tank weapon," a viewpoint that had been expressed by Devers at least as far back as the fall of 1941, by Chaffee before that, and even by Chief of Infantry Major General George A. Lynch in July 1940.General Board, European Theater, Tank Gunnery, 29. General Board, European Theater, The Infantry Division, 6. Adams, 80-1, 89; Wheeler, 160; Gabel, The U.S. Army GHQ Maneuvers of 1941, 33, 124. Baily, 8. Patton had made a similar recommendation during a meeting on 14 January 1945. See GEN George S. Patton, Jr., 220. The January 1946 report by the War Department Equipment Board, headed by General Joseph W. Stilwell, agreed with the General Board, saying, "The best antitank weapon is a better tank."Stilwell et al., 12

The increasing acceptance of the tank as the primary antitank system could only mean supplantation of the specialized Tank Destroyers. The War Department Equipment Board was decisive in its analysis: "The thin-skinned, self-propelled tank destroyer has too limited a role to warrant further development now that comparable gun power can be attained in tank development. Similarly, the towed tank destroyer is outmoded." And later in its report the Board reiterated, "Whereas the typically thin-skinned highly gunned vehicle known as the tank destroyer will always be able to carry more powerful armament for the same overall weight than the corresponding tank, this inherent advantage does not justify the continuation of the development of this class of fighting vehicles in view of the present and future potentialities of tank armament, mobility and maneuverability. Therefore, development of the tank destroyer should be terminated."Stilwell et al., 12, 42. Recommendations from the General Board included replacing the infantry division's antitank companies by an armored regiment, and also having mechanized cavalry squadrons attached to armored or infantry divisions rely on those divisions' organic tanks for protection rather than Tank Destroyer assets.General Board, European Theater, The Infantry Division, 6. General Board, European Theater, Mechanized Cavalry Units, 16. After studying the after-action reports of the forty-nine tank destroyer battalions that fought in Europe, the General Board ultimately recommended that the Tank Destroyer doctrine be revised and included in the defensive doctrine of the Armored Force; armored, self-propelled, high-velocity guns be included in infantry divisions; the Artillery be responsible for deepening the organic antitank defense; and that "the tank destroyers as a separate force be discontinued."General Board, European Theater, Study of Tank Destroyer Units, 29. The recommendation for self-propelled guns for the infantry division would be rescinded in early 1949 by the Army Field Forces Advisory Panel on Armor: see Harmon et al., I: B, 10. These reports sounded the death knell of the Tank Destroyers, and the last units were decommissioned by 1 November 1946.Gabel, Seek, Strike, and Destroy, 65.

Also shortly after the war, engineer Harry Knox instigated an international lawsuit over his designs. As noted above, his patents allowed the US government to manufacture and use his inventions for its own purposes. But during the war, production of various assemblies also occurred in and for the United Kingdom, which Knox claimed infringed upon his patents. America and Great Britain had entered into a Patent Interchange Agreement on 1 January 1942 that stated the former would handle patent infringement claims filed by US nationals after that date, leading to the American and British governments sharing responsibility for Knox's infringements. Negotiations between Knox, the US Department of the Army, and the United Kingdom resulted in a proposed settlement of $24,000 from Britain for infringements prior to 1 January 1942, and a patent release contract and $35,000 from the United States for activity after that date. In a March 1949 letter to Secretary of the Army Kenneth Claiborne Royall, Sr., Comptroller General of the United States Lindsay C. Warren could "perceive no basis for interposing any objection to the execution of the Patent Release Contract and the payment of the consideration covered thereby."Warren, 1-6. "From the Editor: The Forgotten Legacy of Harry Knox," <https://tankandafvnews.com/2015/01/29/from-the-editor-the-forgotten-legacy-of-harry-knox/#more-57>.

Structural changes abounded for armored troops in the latter half of the 1940s. The Armored Center was deactivated on 20 October 1945, but it was soon resurrected in November 1946. Armor officers were assigned to the Cavalry in the interim. The next year, the armored division was revamped. The new armored division would be composed of three equal combat commands and the addition of a fourth infantry battalion, a heavy tank battalion, a 155mm self-propelled howitzer battalion, and an antiaircraft battalion. The infantry battalions in the armored division grew from three to four companies each, and a total of 361 tanks was fielded. AGF published a plan in October 1946 to reduce branch parochialism by establishing three branches of the Army--infantry, artillery, and armor--and assigning cavalry missions to the proposed armor branch; in April 1947, the War Department made its own moves to combine the Cavalry and armored forces into a single Armored Cavalry branch. AGF was taken out of the picture in March 1948, however, when it was rechristened Army Field Forces and had its responsibilities reduced to supervising and inspecting troop training. The issue was settled on 28 June 1950 with the Army Organization Act of 1950, when the earlier AGF proposal was essentially put into effect. Armor was finally certified as a permanent branch of the Army, and the Cavalry--which had taken in the disbanded EMF almost two decades earlier, had given the country the basis for its first armored division, and had even given the Armored Force its first commander--had its independence revoked and was subsumed by the new Armor branch.Wheeler, 447-8, 459-60. Ogorkiewicz, Armoured Forces, 94-5. Yeide, Steeds of Steel, 273. Green, War Stories of the Tankers, 10. Cameron, Mobility, Shock, and Firepower, 510. Cameron, To Fight or Not to Fight?, 117. Morton, 217. Hofmann, Through Mobility We Conquer, 288, 454, 456, 464. The War Department Equipment Board had also called for Cavalry's cessation as a separate arm in their report. See Stilwell et al., 9, 13, 20.

Despite these plans and legislations, the armored forces of the United States were again drawn down to skeleton-crew levels. By 1948 there were but ten active regular divisions in the Army. Only the 2d Armored Division remained active of the sixteen formed for the war, and this division fielded a single combat command. Likewise, the country's immediate-post-war fleet of 28,000 tanks was reduced to a mere 6,000 serviceable machines by 1950."Armored Force, Command, and Center," 110-1. Doughty, 15. Ogorkiewicz, Technology of Tanks, I: 30. Cameron, To Fight or Not to Fight?, 112. Cameron, Mobility, Shock, and Firepower, 509. Hofmann, Through Mobility We Conquer, 462. According to Stone, 38, the ratio of armored to other divisions had decreased to the single armored division in fourteen divisions by 1950. Amid this precipitous decline of available vehicles, the Army Field Forces Advisory Panel on Armor, chaired by retired Major General Ernest N. Harmon, released a report in February 1949 that warned, "Unless our tank development situation is improved, we cannot expect to have enough tanks to support a major ground conflict for at least two and a half years after an emergency is declared to exist."Harmon et al., I: B, 7. Qualitatively, the report claimed, "the U.S. Army today has no tank in production or in development capable of meeting the most numerous and powerful types of tanks possessed by our potential enemy in large quantities." Although continuing work on individual components ensured that "tanks capable of defeating those of our potential enemy can be developed and put into production...a period of approximately three years will elapse before the production of [these new designs of] tanks can be realized."Harmon et al., I: B, 5.

Recently-invented weapons influenced the post-World War II demobilization. Primarily, the advent of nuclear weapons and the deterrence conferred by America's nuclear hegemony seemed to indicate a lessening role for military ground forces since the US could respond to aggression with atomic aerial strikes. The Army still posited that ground forces would be necessary even after a nuclear strike, and the end of the nuclear monopoly with the Soviet Union's successful atomic bomb test in 1949 forced a rethinking of the nuclear deterrence policy and ground forces' place within it.Doughty, 2. Trauschweizer, 18, 25. Bacevich, 12-15, 31-3. The shaped charge was another element that played a part in the reduction of American mechanized power, as a burgeoning viewpoint held that the pendulum of advantage had swung away from armor and firmly to antitank weapons with its development. In World War II, handheld launchers firing shaped charge projectiles such as the American bazooka, British PIAT, and German Panzerfaust and Panzerschreck had enabled individual soldiers to knock out the heaviest of tanks.Indeed, Germany's Jagdtiger was the heaviest vehicle fielded during World War II, and the first one lost in combat was knocked out by an American bazooka team. See Devey, 2: 192, 194. This power was combined with rapid proliferation: Allied tank casualties caused by shaped charge weapons in western Europe and Italy increased from 10% in early 1944 to 25-35% by the spring of 1945.Coox and Naisawald, 2. Considerations such as these colored thinking even at the highest levels: both Secretary of the Army Frank Pace and Army Chief of Staff General Joseph Lawton Collins publicly declared in early 1950 their belief that tanks were obsolescent.Ogorkiewicz, Tanks, 149-50. Icks, Light Tanks M22 Locust and M24 Chaffee, 104. Estes, M103 Heavy Tank 1950-74, 16.

Soon after Secretary Pace's pronouncement, however, North Korea's invasion of its southern neighbor on 25 June demonstrated both that conventional conflicts were still a possibility in the nuclear age and that armored vehicles would be important components in these conflicts. The unfortunate combination of budgetary constraints that allowed armored vehicles to fall into disrepair and concerns over damage medium tanks would cause to Japanese roads while on occupation duty meant that the heaviest American tanks readily available in the region were light M24 Chaffees. This would haunt the first US forces into South Korea: compared to North Korea's spearhead of Soviet-designed T-34-85 medium tanks, the Chaffees were wholly inadequate. Indeed, the seventy-three M24s committed to the theater in 1950 only managed to knock out a single T-34-85, which was set aflame by a spreading house fire caused from an M24 unit's shelling of the village in which it was hiding. Philip L. Bolté, "Post-World War II and Korea: Paying for Unpreparedness," in Camp Colt to Desert Storm, 225. Hunnicutt, Stuart, 441. Coox, 14-5. Medium tanks were rushed to the theater after many were reconstructed in Japan, eventually allowing the M24s to resume their usual role of reconnaissance and security.Hunnicutt, Pershing, 178. Hunnicutt, Sherman, 494-5. Forty-five percent of tanks sent to Korea in the conflict's first half year had been overhauled or rebuilt in Japan; see Gough, 59. The situation was desperate enough that Army Reserve and National Guard units were canvassed for equipment to transfer to active units, and among the items diverted to the active Army in the first year of the war were 750 tanks.Gough, 35.

Light tank M24 Chaffee

The first M4 Shermans arrived in Korea on 31 July 1950, with M26s and the improved M46 Patton following in early August.Hunnicutt, Pershing, 180. Hunnicutt, Sherman, 496. Hunnicutt, Patton, 25. Once in action, medium tanks showed their worth. The Sherman's later guises (i.e., 76mm gun tanks and 105mm howitzer tanks) were still useful, and the 76mm gun was able to hole the T-34-85 at combat ranges: preliminary data from 1950 indicated the 436 Sherman gun tanks in the theater knocked out forty-five T-34-85s.Hunnicutt, Sherman, 497. MacDonald et al., 166. Withers, 23. Coox, 19-22. With the 233 M26s in the theater taking out thirty-two T-34-85s and the 158 M46s causing nineteen North Korean tank casualties, the more powerfully-armed 90mm gun tanks proved even more proficient at antitank work.Hunnicutt, Pershing, 187. Coox, 19-22. The 90mm HVAP shot was even found capable of going completely through a T-34-85 at close range.Gilbert, Marine Corps Tank Battles in Korea, 34-8. MacDonald et al., 17.

Medium tank M4A3(76)W HVSS Sherman

Lingering design decisions ensured that the secondary armament of tanks was less successfully utilized than their main guns, however. World War II tankers had felt that the existing antiaircraft machine gun mounts were hard to use, and late in that conflict the Third US Army had provided a handier location for the rooftop machine gun. This change, when included with others performed by the Third Army like welding extra armor plate to tanks, was impressive enough that the 12th Army Group suggested to the Ordnance Department that standardization be approved.General Board, European Theater, Tank Gunnery, 35. Zaloga, Patton versus the Panzers, 236. Nonetheless, in 1949 the Army Field Forces Advisory Panel on Armor noted that a requirement remained for a dual-purpose small caliber weapon "readily available to the commander" of combat vehicles, but because extant machine guns "normally cannot, because of their location, be fired by the vehicle commander personally", a "more suitable mount should be developed for the dual purpose machine gun mount on top of the tank turret."Harmon et al., I: Sec. IX, Pt. 5, 2-3; Sec. IX, Pt. 10, 7. Seeking their own remedy, enterprising crews in Korea echoed the earlier Third Army efforts by relocating the .50 caliber machine gun on some M26s to a more accessible spot in front of the commander.Gilbert, Marine Corps Tank Battles in Korea, 18-9. The mount 6580030 finally appeared on the M46, allowing the machine gun to be mounted in front of the commander over the gunner's periscope.

Medium tank M26 Pershing

The Sherman emerged as the most dependable tank in US service, but mechanical issues were troubling enough that more tank losses were caused by breakdowns than by enemy action in the first year of the conflict.Shields et al., 111. MacDonald et al., 23-8. All tank types had to deal with scarce mechanics and parts shortages caused by the hostile and mountainous terrain, but the M46 further suffered from unfamiliarity with its new engine and powertrain. The failure rate for this tank may have been artificially increased, however, as one battalion so equipped "made it a policy to evacuate to ordnance practically all tanks with some mechanical difficulty. Other units merely treated such mechanical difficulties as routine unit maintenance and did not classify them as mechanical failures." The initial lack of available medium tanks was also a factor that influenced reliability: the M26 was the most vexatious tank in the first year of the war, but some of these had been desperately shipped to Korea despite already needing repairs or even overhauls. Quoted in MacDonald et al., 28; 68-9. Shields et al., 111-3.

Medium tank M46 Patton

The war entered a more static phase after 1950, where tanks were often used as artillery, for bunker reduction, or statically in commanding positions atop hills or ridges. Tanks were still very active during this period: M26s and M46s fired enough 90mm ammunition that a shortage in US stocks was encountered; one reason was that tanks in positions on hilltops needed to keep the enemy suppressed or else return fire would be received.Gilbert, Marine Corps Tank Battles in Korea, 227. Ravino and Carty, 251. Colton, 11-3. Sherman tanks were often preferred over the newer types during this period since the M4s could navigate the Korean terrain more easily than their heavier replacements. For example, the M26's torqmatic transmission could slip if the tank stopped on steep hills, sometimes necessitating an initial push from a Sherman. Size also mattered: a Provisional Tank Platoon comprised solely of Shermans was formed by the Marines on 18 November 1950 to patrol the Main Supply Route past Majon-dong since the road was simply too narrow for the wider M26s.Gilbert, Marine Corps Tank Battles in Korea, 23, 107-9; and Ravino and Carty, 65. In part due to this mobility advantage, the Sherman ended up being the most numerous American tank in the theater when the armistice was signed in 1953.Hunnicutt, Pershing, 187. Hunnicutt, Sherman, 503.

Like many of the tanks, self-propelled artillery vehicles in Korea were holdovers from World War II due to lack of funding for newer designs. The 105mm HMC M7B1 suffered in the mountainous theater due to its limited elevation, a relatively paltry 35°. A workaround was performed in the M7B2 by raising the howitzer mount along with the machine gun ring mount, increasing the maximum elevation to 65°.Hunnicutt, Sherman, 341. Crismon, U.S. Military Tracked Vehicles, 170. Both the 155mm GMC M40 and the 8" HMC M43 also saw active service in Korea. Based on the M4 Sherman with the later horizontal volute spring suspension, production had been ordered for the two vehicles in February and April 1945, respectively. Only a single pilot example of each participated in World War II during the early-1945 Zebra Mission, but both types engaged in extensive fighting in Korea.Hunnicutt, Sherman, 353-5. Doyle, M40 Gun Motor Carriage and M43 Howitzer Motor Carriage, 36.

155mm gun motor carriage M40

Although armored engagements in the Korean War were largely small and decentralized, lessons were still extracted. Among the recommendations submitted was a suggestion in 1951 by the Operations Research Office (ORO) of the Far East Command to reinforce combined arms training, since at times the cooperation between armor and infantry was inefficient. In part, more radios were desired, since the tanks' infantry phones were prone to damage and their use required the infantry to expose themselves to enemy fire.MacDonald et al., 40-1, 169. Bolté, 253-4. Doughty, 8. A 1954 ORO report asserted that better night training and night vision equipment would be beneficial since many enemy attacks were staged after dark to lessen the potential of UN air support, artillery, and armor.Bolté, 255.

Despite the Korean War's graphic illustration that limited wars were still a possibility--and even after former Army officer Eisenhower won the 1952 presidential election--Army budgets were continually gutted throughout most the 1950s. Eisenhower now saw conventional ground conflicts as wasteful in both money and manpower, and by the middle of the decade he would be convinced that a nonnuclear war with the Soviet Union was unwinnable.Carter, Forging the Shield, 80, 289. Carter, The U.S. Army Before Vietnam, 20-1. Under his administration's New Look policy the Air Force, with its intercontinental nuclear delivery methods, grew to dominate military funding. In 1953, with the fighting in east Asia still ongoing, the Army received $13 billion, down $8 billion from the year before and much less than the Air Force's 1953 budget, which eclipsed $20 billion. After the fighting in Korea had ended, in 1955 the Army received $7.6 billion and had both its total active divisions and personnel strength cut by one-fourth. By 1957 the Army budget had been further reduced to $7.5 billion. Compared to 1950, the Army's 1957 budget had increased by less than half, while the Air Force's $16.5 billion 1957 funds represented a trebling of its 1950 budget. After the Soviet Union launched the Sputnik satellite in October 1957, US military spending increased, but the proportion of Army to Air Force spending remained similar, with the Air Force almost doubling the Army's budget.Bacevich, 15-7. Trauschweizer, 26, 29-30, 65-7. Carter, Forging the Shield, 208-9.

Of the money the Army did receive, a large portion was devoted to the development of satellites and surface-to-air and nuclear-capable surface-to-surface missiles in an effort to show that the Army was modernizing itself beyond stereotypical equipment. Tactical nuclear delivery systems such as the 280mm motorized heavy gun M65 and the Honest John rocket entered the inventory by 1953, and indeed Major General John Medaris, appointed to head the Army Ballistic Missile Agency, opined to Ordnance Corps officers that "conventional weapons...are going to get very little money of any kind" while "items that are popular" would be "far easier to justify" in budgets.Quoted in Elliott V. Converse III, "Into the Cold War: An Overview of Acquisition in the Department of Defense, 1945–1958," in Providing the Means of War, Shannon A. Brown, general ed., 29. This was an astute observation, as Defense Secretary Charles Wilson would at one point deny an Army budget request until it was rewritten to contain higher-technology items.Trauschweizer, 56. Carter, Forging the Shield, 253-5. As a result, in 1957 the Army spent almost ten times as much on missiles and nuclear weapons as it did on new vehicles.Bacevich, 71-101. This monetary imbalance was in spite of the fact that the North Koreans' tank vanguard rekindled such interest in armored units that by 1956 four out of the Army's twenty divisions were armored.Doughty, 15. Ogorkiewicz, Armoured Forces, 30. By 1960, the mix had changed to three armored and one cavalry division out of fifteen active divisions. See Carter, The U.S. Army Before Vietnam. 10.

762mm truck-mounted rocket launcher M289

The declining influence of armored forces in the US Army contrasted sharply to contemporary Soviet thinking. After World War II the Soviet Army had maintained its armored forces at essentially wartime levels while slashing the number of infantrymen in its ranks.T.R.W. Waters, "The Traditional Soviet View," in Armoured Warfare, 188. Ogorkiewicz, Armoured Forces, 102. To advocates in each country, armored forces seemed to be ideal for the nuclear battlefield due to their mobility, communications, firepower, and hardiness against blast and radiation. The old military principle of concentration had become a dangerous tenet because of the vulnerability of massed forces to atomic weapons, but armored vehicles allowed a dispersed approach march, last-minute concentration for an attack, then rapid dispersal again. Furthermore, the speed of armored troops would allow them to quickly follow up on holes blasted in the enemy line by nuclear fires.Doughty, 13, 15. Trauschweizer, 57. Ogorkiewicz, Armoured Forces, 33. Bacevich, 66-70, 108-14. "Atomic Battlefield and Armor," 18. The October 1966 edition of FM 17-1 Armor Operations went so far as to say these characteristics made armored vehicles "particularly suited to a nuclear environment", 6, 9. Erickson, Hansen, and Schneider, 27, 56, 67, 73, 81, 83-4, 87-8, 90, 97. For a Soviet perspective, see Chief Marshal of Armored Forces Pavel A. Rotmistrov, "On Modern Soviet Military Art and Its Characteristic Features," in The Soviet Art of War, Scott and Scott, eds., 145. However while the US Army was funneling an increasing amount of money and effort away from armor towards more "modern" systems, at the 20th Congress of the Communist Party in February 1956, Soviet Defense Minister Marshal of the Soviet Union Georgy K. Zhukov asserted that, "...we proceed from the fact that the latest weapons, including weapons of mass destruction, do not reduce the decisive role of the ground armies, navies, and aviation. Without strong ground forces, without strategic, long-range and frontal aviation and a modern naval fleet, without well-organized cooperation between them, modern war cannot be waged."Quoted in Pavel A. Chuvikov, "Factors Determining the Fate of Contemporary War," in The Soviet Art of War, 135. See also Simpkin, Deep Battle, 67-9.

Though handicapped by the budgetary concentration on missilery, tank development and procurement did press on in the 1950s. Progress was partly sparked by the North Korean invasion, which was seen as having a real chance of escalating into a "major ground conflict" that the Army Field Forces Advisory Panel on Armor had predicted would cause a drastic tank shortage.The Korean invasion was taken seriously enough that, as a hedge against a potential related Soviet attack into western Europe, President Harry Truman in September 1950 agreed to heavily reinforce American troops in West Germany, including reactivating the Seventh Army and sending over four additional Army divisions. See Carter, Forging the Shield, 13-4, and Carter, The U.S. Army Before Vietnam, 8. Intended to preempt this scenario, the M47 Patton 47 was created by mating a hull based on that of the M46 with the turret designed by the Ordnance Tank and Automotive Command's Joseph Williams for the concurrent medium tank T42 project, which Army Field Forces considered too automotively underpowered for service.Hunnicutt, Patton, 34-5, 52-3. Ogorkiewicz, Technology of Tanks, I: 45. "Mr. Joseph Williams, Ordnance Corps Hall of Fame Inductee 1979, U.S. Army Ordnance Corps," <https://goordnance.army.mil/hof/1970/1979/williams.html>. With the potential tank drought causing near panic, the vehicle entered production in June 1951 before testing had been performed. Consequently numerous modifications to the fire control system--including the deletion of the planned two-axis gun stabilizer--required institution before the tanks could be issued, and upon deployment to Europe the tanks suffered from failures of assemblies including auxiliary generator engines, shock absorbers, master junction boxes, tracks, and final drives.Hunnicutt, Patton, 55-9. Oscar C. Decker, "The Patton Tanks: The Cold War Learning Series," in Camp Colt to Desert Storm, 303-4. Carter, Forging the Shield, 125-6. Hilmes, 83. Additionally, hearkening back to the Army Field Forces Advisory Panel on Armor's 1949 request, the design still lacked a cupola that would allow the commander to effectively engage ground and air targets with his machine gun.Icks, M47 Patton, 227. Despite these debits, however, the M47 was the first production tank to feature an optical rangefinder,Hilmes, 11, 43. though a portion of the population found it difficult to achieve the visual acuity required to service the stereoscopic-style rangefinder chosen. The M47 was supposed to be no more than an interim design until the M48 could be unveiled, but almost nine thousand M47s were eventually constructed.Hunnicutt, Patton, 59, 79. Decker, 304. A further side effect of the potential tank shortage was the US government becoming the largest buyer of new British Centurion tanks behind Britain herself. The US distributed these tanks to its European allies under the Mutual Defense Assistance Program starting in the early 1950s.Munro, 135-8. Dunstan, 22.

90mm gun tank M47 Patton 47

The M48 Patton 48 was accepted in early 1952, quickly replacing the trouble-prone M47 in Army units after the tank crisis period had passed. This fresh start featured an elliptical hull and turret design pioneered by Joseph Williams, with contours similar to those used in the heavy tank M103--also penned by Williams--which was still under development at that point. This shape promised to save the most volume and weight for the protection offered, and a 1954 study further asserted that its complex, curving surfaces would present an angle of obliquity of at least 56° to fully half of random hits fired from the ground at 0° elevation.Hunnicutt, Patton, 83. Hunnicutt, Firepower, 114. Goldman and Kempinger, 10. Estes, M103 Heavy Tank 1950-74, 8, 13. Offensively, the M48 housed a sophisticated fire control system: an electromechanical ballistic computer calculated superelevation based on input data from the rangefinder as well as other factors, and this computer was connected to the sighting devices by ballistic drive linkages so that the proper superelevation could automatically be applied to the commander's rangefinder and gunner's periscope, the reticle of which was then centered on the target to apply the correct superelevation angle to the gun.Hilmes, 83. FM 17-79, 38-48. TM 9-7012, 58-9, 66-9, 96-7. Hunnicutt, Patton, 94. Icks, The M48-M60 Series of Main Battle Tanks, 7. Soviet tank fire control systems would not surpass this complexity until the late 1960s and early 1970s when similar systems were installed on the T-64 and T-72, but with the additions of stabilization and an automatic range compensator that took the tank's own movement into account."Tankograd: T-72: Part 1," <https://thesovietarmourblog.blogspot.com/2015/05/t-72-soviet-progeny.html>; "Worldwide Tank Fire-Control Systems," 32-5. Like its immediate predecessor, the M48 entered production before testing had been completed, and consequently the Controller General of the United States published a report in 1960 detailing the tank's mechanical deficiencies, which included thrown tracks, suspension failures, a difficult to use rangefinder, and a transmission that initially allowed shifting into reverse while the tank was moving. Modifications were introduced to correct these problems.Icks, The M48-M60 Series of Main Battle Tanks, 4-6. The M48A1 was finally topped with a cupola that enclosed both the commander and his machine gun, allowing its use and replenishment from under armor.

90mm gun tank M48 Patton 48

The M48 was not even three years old when the T95 program was begun in January 1955.Decker, 308. Hunnicutt, Abrams, 44. Intended to field a vehicle that was lighter but more powerful than the M48, the T95 was to incorporate such novelties as the pulsed-light Optar rangefinder and a rigidly-mounted hypervelocity 90mm smoothbore gun firing armor-piercing fin-stabilized discarding sabot (APFSDS) penetrators.Decker, 308. Hunnicutt, Abrams, 50, 61. Ogorkiewicz, Technology of Tanks, I: 48. Hilmes, 43. Progress on the T95 dragged, and in 1958 the Bureau of the Budget announced that after fiscal year 1959 it would require an improved tank and would no longer authorize purchase of the then-current M48A2.Decker 309. Hunnicutt, Patton, 152. Hunnicutt, Abrams, 90.

90mm gun tank M48A2 Patton 48

The Army had anticipated this and, since many components of the T95 were still being tested and it would not have offered a great advance over the M48A2 in any case, decided to simply increase the range and firepower of the tank it was already using. This new version was dubbed M60 to differentiate it from the M48A2 whence it was derived, and it was accepted into service in 1960. Its powerful M68 gun was based on the British 105mm L7 that was concurrently being installed in the Centurion, and its diesel engine greatly improved fuel efficiency over even the fuel-injected M48A2. The cost of fuel had become such a burden on the tight Army budget that in September 1957 the Seventh US Army in Germany was forced to order that only wheeled vehicles would be utilized during practice alerts.Carter, Forging the Shield, 263. Siliceous cored armor was mooted for the M60's turret and hull to help further protect against shaped charge attack, but high costs and a dearth of manufacturing capacity for the armor led to homogeneous steel being used.Hunnicutt, Patton, 152-3, 156. Decker, 309-10.

The M60 quickly produced a response in the Soviet Union. Work there was being conducted on a prototype tank called Obiekt (Ob.) 166 armed 115mm smoothbore gun, but progress was floundering due to political turmoil caused by competition between manufacturers. Upon being briefed in January 1961 about the introduction of the L7 and M68 and their advantages over the 100mm rifle in the USSR's current T-55 tank, Marshal of the Soviet Union Vasily Ivanovich Chuikov, commander in chief of Soviet Ground Forces, raged at members of the Glavnoye Bronetankovoye Upravleniye (GBTU; "Main Armored Directorate") to get the 115mm gun into service as soon as possible. Ob.166 quickly matured into the T-62 after the red tape was cut, and pre-series examples reached Soviet Army units that fall.Hull, Markov, and Zaloga, 50-1. Kinnear and Sewell, Soviet T-62 Main Battle Tank, 23-5.

105mm gun tank M60

The Marines also worked to acquire modernized tanks, and with Pacific Theater combat experience in mind, eliminated the requirement for light tanks on 15 April 1949.Estes, M103 Heavy Tank 1950-74, 10. Although it was realized that designs with more armor than the venerable Sherman were needed, the Marines initially balked at the increase in weight that the extra protection imposed.Alexander, 213. The Pershing was only fully integrated into Marine armored units in 1949, with 102 acquired by 1950, and this seemed a wise choice after the North Korean invasion with its spearhead of T-34-85s.Kenneth W. Estes, "The Marine Corps's Struggle with Armor Doctrine during the Cold War (1945-70)," in Camp Colt to Desert Storm, 266. Estes, M103 Heavy Tank 1950-74, 5-6. The M46 started replacing Marine Pershings in July 1951, M47s began arriving in October 1951, and the M48 entered their inventory in 1954.Estes, "The Marine Corps's Struggle with Armor Doctrine during the Cold War (1945-70)," 278, 281-2.

Both branches employed the single post-war heavy tank that entered service, but the Corps retained it long after the Army had given up on the machine. The M103 was racked by teething problems upon its introduction, and initially the Marines alone accepted the M103A1.Hunnicutt, Firepower, 123-4, 140. Estes, M103 Heavy Tank 1950-74, 21-2, 24-5, 28. The Army was so impressed with the modifications, however, that it borrowed seventy-two M103A1s for its heavy tank battalion in Europe until 1962. The further improved M103A2 remained in the Marine Corps arsenal until 1972.Hunnicutt, Firepower, 140. Estes, "The Marine Corps's Struggle with Armor Doctrine during the Cold War (1945-70)," 285. Estes, Marines Under Armor, 150-3. Estes, M103 Heavy Tank 1950-74, 29-30, 32, 40. Britain's Conqueror tank, analogous to the M103 and armed with a similar 120mm rifled gun, served until 1967. See Griffin, Conqueror, 148.

120mm gun tank M103

Organizationally, a tank battalion was retained in each Marine division after World War II, and corps-level force tank battalions were also formed. In 1957, however, armored units in these formations were removed in the interest of achieving helicopter-borne air transportability. Heavy equipment like tanks and amphibian tractors were taken from the divisions and given to centrally-held Force Troops. The 1st and 2d Tank Battalions were changed to incorporate heavy tanks, each with two medium and one heavy tank companies (a fourth company would be added during wartime), while the 3d Tank Battalion remained a medium tank battalion.Estes, Marines Under Armor, 133, 156-8.

The Army launched a detailed analysis of its tank program in the mid-1950s which culminated in May 1957; the submission of the official report occurred the following January. Designed to anticipate tank armament post-1965, the so-called Ad Hoc Group on Armament for Future Tanks or Similar Combat Vehicles (ARCOVE) came out with two far-reaching suggestions. Tank gun development was thought to be reaching the point of diminishing returns, and it was postulated that an ideal vehicle armament would be able to destroy all required armored and soft targets yet have a light enough weight and small enough recoil force to make the characteristics of the mounting platform essentially irrelevant. Thus, ARCOVE recommended that the Army concentrate on missile-armed tanks at the expense of kinetic energy weapons. Going along with the preference for missiles, continuing research on chemical energy penetration was urged. A short-barrel 152mm gun-launcher that fired conventional ballistic projectiles as well as the concurrently-designed Shillelagh antitank missile was proposed in early 1959, and several specifications from this early study matched the finished product precisely or almost exactly, including the use of combustible cartridge cases and a separable chamber, chamber volume, bore length, projectile travel in bore, projectile and complete round weight, and muzzle velocity. Secondly, in a break from the traditional light, medium, and heavy tank classes desired as recently as 1949 by the Army Field Forces Advisory Panel on Armor, ARCOVE predicted the future tank force would be composed of only two types: a light reconnaissance and airborne assault vehicle and a new class of vehicle called a main battle tank (MBT). This new type of tank would combine the former medium and heavy tanks into a single machine, having the mobility of the former and the firepower and protection of the latter.Hunnicutt, Patton, 149-50. Decker, 311. Ogorkiewicz, Tanks, 167-8. DeLong, Barnhart, Cagle, 10-1, 130-1, 137. Harmon et al., I: B, 6; Sec. III, 11-2. Technical Study and Proposed Development Program for a New Tank Main Armament System (U), 7-8, 10, 15, 21, 23, 26-35. For comparison of specifications for the projected gun-launcher with the production M81 and XM162E1, compare Technical Study and Proposed Development Program for a New Tank Main Armament System (U), 16, 23, 32, with Hunnicutt, Sheridan, 329, and Hunnicutt, Patton, 455. The previous desire for separate classes is espoused by, e.g., Harmon et al., I: B, 7, said, "A single 'universal' tank to fill the role of both the medium and heavy tanks is not tactically sound or economical." The desirability of the MBT concept as opposed to the continued use of separate medium and heavy tanks was echoed in October 1957 during the Fourth Tripartite Conference on Armor between the US, UK, and Canada.Griffin, Chieftain, 13.

Infantry was not left behind, so to speak, during the early Cold War years. From their trundling beginnings, tanks had quickly gained enough power and speed to necessitate motorized transportation for the accompanying footsoldiers. The half-tracks of the early 1940s possessed only marginal protection and off-road mobility, and the advent of variable-timed artillery shells and atomic weapons obsoleted all open-topped designs.Haworth, 17-8. "Armored Force, Command, and Center," 91. Harmon et al., I: Sec. VIII, 1-2. The development of fully-enclosed and fully-tracked infantry carriers started even before the end of World War II: the armored utility vehicle M44 was the first purpose-built design, but was cancelled due to its very large size and the disappearance of funds following the end of the war.Haworth, 23. Hunnicutt, Bradley, 30-2. Ogorkiewicz, Design and Development of Fighting Vehicles, 157. Harmon et al., I: Sec. VIII, 3. The armored personnel carrier (APC) M75, which entered service in 1952, was smaller than its predecessor, but there were concerns that it was excessively expensive during an era when budgets were dominated by atomic weapons.Haworth, 23-4. Hunnicutt, Bradley, 48. The APC M59 began replacing the M75 the following year, and thankfully for the Army cost about one-fourth as much as the M75. The M59 achieved this price difference largely by using two commercial GMC truck engines instead of the specialized powerplant of the M75, which was related to that found in the 76mm gun tank M41 Walker Bulldog.Haworth, 24. Hunnicutt, Bradley, 62. Ogorkiewicz, Design and Development of Fighting Vehicles, 160-1. Unfortunately these cost savings were somewhat mitigated by the additional maintenance burden of having to keep the two engines synchronized.The 13th Armored Infantry Battalion Assoc., 39-40, 167. While being cheaper than the M75, the M59 was actually heavier. A search for an air-transportable armored personnel carrier began, ending in 1960 with the introduction of the M113, which weighed about half as much as the M59 thanks to its trimmer size and the use of aluminum rather than steel armor. It was also more mobile than its antecedent, which would prove very beneficial as the M59 would have trouble keeping pace when paired with the new M60 tanks.Sorely, Press On!, I: 96, 99. The M113 became the most-produced American armored vehicle in history, and was modified to fill an almost uncountable number of roles.

Armored personnel carrier M75

The overall shape of the APC had changed little from the M44 to the M113: they were all essentially armored boxes on tracks. Also, the basic mission of all these new vehicles hearkened back to the half-tracks of World War II: they were to transport infantry as close as possible to their objective, where the troops would dismount and fight on foot.Haworth, 25. Harmon et al., I: Sec. VIII, 2. Ogorkiewicz, Design and Development of Fighting Vehicles, 163. Bellanger, 228, 289. FM 17-42, 1-2, 63-6. FM 17-20, 62. Doughty, 23-4. Simpkin, Mechanized Infantry, 28. Carter, Forging the Shield, 326. The 13th Armored Infantry Battalion Assoc., 3-5, 86. As far back as 1949, however, Army thinkers had posited, "The optimum situation will occur when the infantry can reach its objective without having to dismount at all."Harmon et al., I: Sec. VIII, 2. The search for a vehicle that could realize this ideal by providing the carried troops the ability to fight while mounted would drive the protracted development of an entirely new class of infantry carrier.

Armored personnel carrier M113

Just like its land-based counterparts, the open-topped tracked landing vehicle was also eliminated by the threat of airburst artillery and nuclear weapons. The LVT3, on which the US had standardized after World War II, acquired a folding aluminum cargo cover beginning in 1949.Hunnicutt, Stuart, 274. Hunnicutt, Bradley, 323-4. The cargo cover also helped prevent water from entering the cargo area and swamping the vehicle. See Research, Investigation and Experimentation in the Field of Amphibian Vehicles, 61; Croizat, 201; and Estes, Marines Under Armor, 112. The vehicle's armament, which had consisted of machine guns mounted in the cargo compartment, was then necessarily rearranged: a machine gun turret was added to the roof and a second machine gun was mounted in the bow. The improved vehicle was designated LVT3(C) and served until being replaced by the LVTP5, which along with its engineer, recovery, and command variants, was introduced in the mid-1950s. A 105mm howitzer version of the LVTP5 was also accepted, replacing the LVT(A)5.

LVTH6

The infiltration tactics of the enemy in Korea and the potential isolation caused by the nuclear battlefield envisioned in the early 1950s highlighted the necessity of 360° traverse for artillery vehicles' armament. But like the tank crisis that led to the M47, a perceived deficiency of self-propelled artillery spurred the Army into quickly accepting a crop of vehicles that lacked this and other desired features. These new machines were the 105mm self-propelled howitzer (SPH) M52, 155mm self-propelled gun (SPG) M53, 155mm SPH M44, and 8" SPH M55. Accepted before testing on them had been completed, modifications to fix numerous problems with the vehicles had to be performed after they had been put into service. These heavy vehicles were also unable to be air-transported, a characteristic that was becoming increasingly attractive to Army planners.Dastrup, King of Battle, 255, 259-60, 268-70. Hunnicutt, Patton, 255-7. Hunnicutt, Sheridan, 198-202.

105mm self-propelled howitzer M52A1

Solutions to the artillery dilemma started to reach the field in late 1962 with the advent of the 105mm SPH M108 and 155mm SPH M109. These vehicles had turrets with 360° traverse and, like the M113, incorporated aluminum armor to decrease weight and ease transportation by plane. Two new heavy artillery vehicles, the 8" SPH M110 and 175mm SPG M107, were introduced at the same time. Although they lacked enclosed turrets and all-around traverse, the light weight conferred by their almost complete absence of armor made them air-transportable as well.Hunnicutt, Sheridan, 207-9, 221-3. Dastrup, King of Battle, 277.

155mm self-propelled howitzer M109

In October 1956, Army Chief of Staff General Maxwell Taylor announced a reorganization of the Army's fighting formations to better prepare for a nuclear battlefield. These new divisions were intended to use five relatively self-sufficient battlegroups each consisting of five companies, each of these having five platoons, that would be able to fight dispersed and in depth in a warzone ravaged by nuclear fires. Reflecting the number of battlegroups/companies/platoons and their utility on an atomic battlefield, the new divisions were dubbed "pentomic" (pentagonal/atomic). The infantry division was heavily redesigned and included a 5-company tank battalion and a centralized group of APCs that could move a single reinforced battlegroup; nuclear-capable howitzers and rocket launchers were also added. The armored division was only slightly affected by the reorganization, retaining the combat command system and gaining a stronger aviation element and nuclear-capable self-propelled 8" howitzers. The armored division contained fifty-four light tanks and 324 medium tanks in four tank battalions; a central transportation unit gathered all of the armored division's APCs to be doled out as needed, but like the infantry division only a single battlegroup could be transported at a time with the vehicles assigned. With Korea showing the apparent need to quickly deploy forces to trouble spots around the world, airliftable equipment was desired to fill out the new divisions.Trauschweizer, 55, 59. Doughty, 16-7. Bacevich, 104-8. Carter, Forging the Shield, 312.

8" self-propelled howitzer M55

The reaction to the pentomic structure was quick and largely negative. The inflexible design of the pentomic units was seen to be too focused on nuclear war to the detriment of conventional operations, the new divisions were thought lacking in conventional artillery and air defense, and there were concerns about the ability of headquarters to effectively control and supply the five widely-separated battlegroups and the large companies within the battlegroups once battle was joined. Soldiers were loathe to give up the proud traditions and lineages of established regiments in favor of the new battlegroups. Also, design and production delays caused shortages of essential new equipment like long-range radios and air-transportable APCs (the M113 only entered service in 1960), and the ability to move only a single battlegroup at a time under armor was a definite detriment to an organization that was intended to operate on contaminated battlefields.Trauschweizer, 55, 108-10. Doughty, 18-9. Bacevich, 100-1, 117-8, 134. Gole, 119-21. Carter, Forging the Shield, 299-300, 303-7, 309, 312. Carter, The U.S. Army Before Vietnam, 28-31. Dastrup, King of Battle, 272-5.

Beginning in 1962, the Army transitioned to the Reorganization Objective Army Division (ROAD), which corrected many of the perceived faults of the pentomic division. The ROAD formations were similar in concept to how the armored division had operated since World War II in that three brigade headquarters were established that could be assigned different battalions depending on the mission, and the different battalion types were standardized with respect to the number of companies to better enable cross-attachment. Armored divisions were given six tank and five mechanized battalions with 324 tanks and 718 APCs, infantry divisions had eight infantry and two tank battalions with 108 tanks, and a new mechanized infantry division was created with three tank and seven mechanized infantry battalions with 162 tanks and 798 APCs. The artillery and aviation assets of the ROAD divisions were increased over the pentomic formations as well. The ROAD divisions were better prepared to conduct conventional operations than the pentomic divisions, which by that point was thought to be more likely than a scenario involving a nuclear exchange. Military spending greatly increased towards the middle of the 1960s, and the funds began to be doled out to either strategic-retaliatory or general purpose forces instead of to the individual branches of the armed forces. This budgetary influx allowed the Army to begin to fill out its new divisions by redressing the previous decade's lack of focus on conventional weapon development and procurement.Trauschweizer, 114-7, 123. Doughty, 19-23. Carter, Forging the Shield, 431-2, 440-4, 446. Carter, The U.S. Army Before Vietnam, 37-9. Dastrup, King of Battle, 275-7.

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Vietnam to Desert Storm: The Struggle for Modernization

The armored forces of the United States experienced another tropical theater when they were deployed to Vietnam. Initially it appeared that no armored forces at all would be sent. Indeed, the first US tanks into Vietnam were unexpected by some US government officials and Army planners: When the 9th Marine Expeditionary Brigade landed northwest of Danang in March 1965, not all realized that its table of organization included an organic tank battalion.Trauschweizer, 175-6. Gilbert, Marine Corps Tank Battles in Vietnam, 28-31. Gott, 23. Stewart, I: 54-5, 59-60. American commander General William Westmoreland sent a message to the Army Chief of Staff in July 1965 saying, "except for a few coastal areas...Vietnam is no place for either tank or mechanized infantry units."Quoted in Starry, Mounted Combat in Vietnam, 56. When the 1st Infantry Division deployed to Vietnam in that same month, its tanks were kept home and its mechanized infantry forces were transformed into dismounted infantry.Starry, Mounted Combat in Vietnam, 55. Trauschweizer, 178. Another source noting the Army's desire to leave armored vehicles at home upon deployment is Mahler, 19. However, a study completed in 1967 showed that tanks could maneuver in 61% of the country in the dry season and 46% during the monsoon season, while APCs could travel around 65% of Vietnam regardless of the rains; counterintuitively, wet weather could increase trafficability for amphibious APCs as higher water levels in streams and rivers served to effectively decrease the height of their banks.Mechanized and Armor Combat Operations in Vietnam, 19, 47-8. Starry, Mounted Combat in Vietnam, 10. Haworth, 30. Lewis Sorely, "Adaptation and Impact: Mounted Combat in Vietnam," in Camp Colt to Desert Storm, 328. Once mechanized forces were unleashed, it was discovered that their speed and firepower allowed them to control twice as much ground as infantry units.Doughty, 35.

Part of the Army's preconceived disdain of armor's utility and suitability in Vietnam was due to the underutilization of American armor advisers, the first of whom arrived in South Vietnam in June 1955. Until 1962, the activities of the advisers in Vietnam were classified as secret, forbidding them from discussing knowledge gained about the terrain and enemy. Once the US became actively engaged, American armored units frequently ignored the thoughts of advisers and South Vietnamese armored officers, leaving American forces to discover on their own lessons that had already been learned.Starry, Mounted Combat in Vietnam, 19-21. For another example of experience being ignored, see Sobel, 110-2.

The main medium tank that would fight with American units in Vietnam was the M48A3 Patton, although small numbers of M48A1s were issued due to a shortage of M48A3s following the 1968 Tet offensive.Starry, Mounted Combat in Vietnam, 129. The newer M60s with their 105mm guns guarded the Fulda Gap in Germany against Soviet armor, since at the time the Army still considered the defense of Europe as its primary mission. In any case, the M48A3 was plenty of tank for Vietnam. Its bulk and 750-horsepower engine allowed it to break trails through the thick jungle, and the 90mm gun was able to utilize a variety of ammunition for both direct and indirect fire.Trauschweizer, 174-5, 177, 179-80. Busting a trail through the jungle was hard on men and equipment, however, and the noise and commotion caused by the vehicles allowed the enemy to emplace mines or ambushes in their path. See Haponski, 136-7. Mahler, 202. Doughty, 35. The lack of an antipersonnel canister round for the M60's 105mm gun influenced the decision to send its predecessor to Vietnam. See Nolan, 13. Indeed, by late 1968 90% of tank main gun rounds being fired were canister. See Sorely, ed., Press On!, II: 971. Unlike the useful 90mm gun, however, the sideways-mounted .50 caliber machine gun in the commander's cupola was prone to jams and solenoid malfunctions, and the cramped cupola provided neither enough outside vision nor enough room for the machine gun's ammunition. Reloading this small supply of ammunition was very difficult even under the best of circumstances. These problems caused some crews in both the Army and Marines to create external mounts for the weapon in spite of the resulting increased exposure to enemy fire, and an Army study even recommended replacing the M1 cupola with the M60's cupola M19.Hunnicutt, Patton, 228. Sorely, ed., Press On!, II: 966. Gilbert, Marine Corps Tank Battles in Vietnam, 26, 162. Peavey, 62. Birdwell and Nolan, 52. Green, War Stories of the Tankers, 143-4. Stewart, I: 416, 570-1. Stewart, Book Two, 91-2, 174, 180-1, 186-7, 381, 937. Stewart, Book Three, 182. Willard F. Lochridge IV, "Night of the Tigers," in Stewart, I: 562. Walker, 156. Mechanized and Armor Combat Operations in Vietnam, 171. Another Vietnam veteran described the M48A3's cupola machine gun as "the worst combat mount ever devised." See Zumbro, Tank Sergeant, 92. A further and familiar practice that sacrificed safety for effectiveness was again carrying extra main and machine gun ammunition into combat, which was officially sanctioned in one Cavalry unit at the squadron level. Stewart, I: 571, 573. Walker, viii-ix, asserts that his squadron headquarters specified that tanks would carry 67 rounds of 90mm, broken down by type, while the M48A3 only stowed 62 rounds. The desire for copious amounts of ammunition extended to the crews of lighter vehicles as well: an Ontos commander and section leader claimed to have stowed over forty 106mm rounds in his vehicle, which was intended to carry a maximum of eighteen.See Stewart, Book Two, 689. Similarly, the space next to the driver in the M42 "Duster" self-propelled antiaircraft gun, typically reserved for the vehicle commander, tempted crews to instead fill it with 40mm ammunition.See Belardo, 101-2, 139.

90mm gun tank M48A3 Patton 48

The M113 APC also served in Vietnam, and the South Vietnamese introduced aggressive new tactics for these vehicles. They mounted an extra machine gun on each side of the rear cargo hatch, provided the commander and extra machine gunners with armored shields designed by their 80th Ordnance Base, and used these modified M113s much like light tanks.Viet, 297, 367. Starry, Mounted Combat in Vietnam, 41-2. Hunnicutt, Bradley, 251. Sorely, "Adaptation and Impact," 331-2. Perrett, 189. Trauschweizer, 176-7. Carter, The U.S. Army Before Vietnam, 39-40. This conversion, dubbed the Armored Cavalry Assault Vehicle, was so successful that standardized kits were procured from the US and sent to Vietnam in 1966.Hunnicutt, Bradley, 252. Spurred on by the dearth of antitank capabilities of enemy forces, US Army forces followed suit and began favoring mounted combat from APCs instead of the previously-emphasized dismounted actions.Mechanized and Armor Combat Operations in Vietnam, 60-8.

Armored cavalry assault vehicle M113A1

The first of the 240 M551 Sheridans deployed to Vietnam arrived in early 1969. Spawned from the ARCOVE suggestion of a light missile-armed airborne assault and reconnaissance vehicle, the M551 was sent to the theater without its Shillelagh antitank missile. The conventional 152mm ammunition could be devastating to enemy troops, especially canister rounds each packed with ten thousand 1.5"- (3.8cm-) long dart-like flechettes. Incomplete combustion of the consumable propellant casing presented problems, though, as burning material could be introduced from the gun breech into the fighting compartment. The closed breech scavenging system was developed to resolve this dangerous situation by using compressed air to clear the breech before it opened. The combustible casing of the ammunition further turned out to be sensitive to the tropical humidity, fragile when not handled carefully, and prone to detonation upon penetration of the vehicle's armor.DeLong, Barnhart, and Cagle, 100-1. Starry, Mounted Combat in Vietnam, 144. Hunnicutt, Sheridan, 107-8, 263-4. Perrett, 190-1. Keith, 12, 301-2. Sorely, ed., Press On!, I: 44, 48. The vehicle was fast and agile but very vulnerable to mines and handheld antitank weapons, and it proved less proficient at jungle busting than the heavier M48A3: breaking a path through the jungle could cause the M551 to overheat.Starry, Mounted Combat in Vietnam, 143-4. Hunnicutt, Sheridan, 118. Perrett, 190. Keith, 12, 116-7, 298-9. Green, War Stories of the Tankers, 181. Haworth, 68-9. Cameron, To Fight or Not to Fight?, 244.

152mm gun-launcher armored reconnaissance/airborne assault vehicle M551 Sheridan

The Sheridan's soggy ammunition was not the only way that Vietnam's humidity and precipitation affected armored vehicles. Water that condensed in a vehicle's fuel tanks, for example, could breed algae that clogged fuel filters. Pumping water out of fuel tanks consequently became a regular maintenance requirement for tankers.Gilbert, Marine Corps Tank Battles in Vietnam, 27. Despite maintenance issues such as these, armored forces grew to become an important part of the Vietnam War. Although their utility in the mountainous jungles was at first far from taken for granted, the first tanks arrived almost by accident with the Marines, and forgotten tank-infantry skills had to be relearned,Gilbert, Marine Corps Tank Battles in Vietnam, 63. the armored units of formations leaving Vietnam were kept in country until last, buying more time for the American pullout.Starry, Mounted Combat in Vietnam, 164-5. Sorely, "Adaptation and Impact," 353.

While the battles of the Vietnam War grabbed headlines in the 1960s, the development of the new MBT suggested in the ARCOVE report and at the Fourth Tripartite Conference began a scant three years after the first M60s were accepted. The war would be long over by the time the finished product appeared, however.Decker, 312-3. Hunnicutt, Abrams, 116. McNaugher, 5. The first effort at a new tank, called MBT70 in the US and Kampfpanzer (KPz) 70 in the Federal Republic of Germany (FRG), was intended to provide a common tank for the US and West German armored forces, and the vehicle itself was stuffed with cutting-edge technology. It featured a 3-man crew, all of whom were in a radiation-resistant capsule in the turret; the driver was interestingly positioned in a counter-rotating cupola in the turret's front corner.This feature, patented in 1964 by Rheinstahl-Henschel AG, hearkened back to and cited in its patent application a tank design patented by Brigadier General Gladeon M. Barnes in 1942. See "General Barnes Tank Patent," <https://tankandafvnews.com/2018/04/05/general-barnes-tank-patent/>. Barnes would eventually rise to head the US Army Ordnance Department's Research and Development Service as a major general. See Green, Thomson, and Roots, 220-6. Rheinstahl-Henschel was a member of the West German general contractor consortium for the KPz70, Deutsche Entwicklungsgesellschaft mBH. See Spielberger, From Half-Track to Leopard 2, 195. This layout was also mentioned in a March 1959 report on the proposed 152mm gun-launcher; see Technical Study and Proposed Development Program for a New Tank Main Armament System (U), 34 The main armament of MBT70 was a longer-barreled automatically-loaded 152mm gun-launcher that was capable of firing high-velocity APFSDS penetrators while retaining the use of the Shillelagh missile. A heavy secondary weapon was included in the form of a retractable 20mm gun positioned to the driver's left-rear that was remotely-controlled by the commander. A laser rangefinder and stabilization for its main weapon helped assure accuracy even while on the move. MBT70 ran on a hydropneumatic suspension that allowed the vehicle to crouch or raise one end of the tank to better take advantage of hull-down positions, and protection was enhanced by the use of spaced armor.

Surface attack guided missile MGM-51C Shillelagh

It was hoped that by sharing the development effort and costs, the complex MBT70 could be produced more cheaply than its Soviet counterparts, but problems plagued the program from the beginning, starting with the countries' very visions and doctrines for the vehicle. The US required a tank that could operate in varied geographical locations while the West Germans were concerned primarily with central Europe. The need for a new tank was much more pressing from the United States' point of view versus that of the FRG, whose new Leopard tank was just entering service in 1965. The US was enamored with the Shillelagh missile's potential for long-range engagements and preferred heavier armor, but the West Germans desired a conventional shorter-range gun and preferred lighter weight and higher speed over armor protection. Basic difficulties with English-German translations, metric to English measurement conversions, and societal differences in manufacturing and designing practices caused considerable headaches throughout the process. Among these latter differences was the fact that the German contractors were securing patent rights for their work in their country, while the government was assigned those rights in the US. Instead of compromising, disagreements were largely settled by adding both sides' desired features to the original design, and both countries duplicated work by creating multiple engines, suspensions, and main armaments. Reliability issues reared up with the variable compression engine being developed by Continental in the US and with the autoloader being worked on by the Germans. The cost and weight of the tank eventually spiraled to unacceptable levels; $287 million had been spent on development between the two countries by the end of 1969, with the US contributing 63% of funding and West Germany 37%. MBT70 was killed in January 1970, leaving each nation to go its separate way.Spielberger, From Half-Track to Leopard 2, 195-203. Robert J. Sunell, "The Abrams Tank System," in Camp Colt to Desert Storm, 433. Trauschweizer, 165-6. Orr Kelly, 25, 30-3, 38. Hunnicutt, Abrams, 117, 142. McNaugher, 4, 6-7, 11-9, 23-6. Hilmes, 20. Walter S. Poole, "Acquisition in the Department of Defense, 1959–1968: The McNamara Legacy," in Providing the Means of War, 88-9. Coincidentally, West Germany's Leopard tank had itself emerged from an earlier failed joint tank program with France, which went on to develop the AMX-30, and Italy, which bought the M60A1. See Shackleton, 1: 10-24; Spielberger, From Half-Track to Leopard 2, 113-29; Robinson, I: 19-34.

The US chose to give the MBT70 another chance, but this time with toned-down technological gizmos. This project was dubbed XM803, and it featured a less powerful engine and simpler hydropneumatic suspension. But even with its budget-saving measures, the XM803 was estimated to cost three to four times as much as an M60A1, and Congress had become especially cost-conscious after the Air Force endured an accounting fiasco with the C-5 Galaxy transport plane and developmental difficulties with its F-111 fighter/bomber. The gun-launcher and Shillelagh missile system were proving troublesome on the M551 and prototype M60A2 tanks, and the Shillelagh was even reproposed as a 105mm supersonic missile with a range of 4km (2.5 miles). In addition to these cost and weapon issues, the legislature was becoming displeased with the lengthy development timeline in which the MBT70 and XM803 were enmeshed. Thus, the XM803 was cancelled in December 1971, after the US had spent a total of 305.4 million contemporary dollars on the MBT70/XM803 programs.Ogorkiewicz, Technology of Tanks, I: 50. Stone, 77. Burton, 13, 18. Orr Kelly, 40-2. Sunell, 433-4. Hunnicutt, Abrams, 158. DeLong, Barnhart, and Cagle, 78, 94-7, 101. McNaugher, 20-1, 26-7, 31-2. The M60A2's gun-launcher was troublesome even after entering service. See DeLong, Barnhart, and Cagle, 104-5.

152mm gun-launcher tank M60A2

The M60 was over a decade old when work on the XM803 was stopped, and the US was forced to start fresh on its replacement. As it made funds available for a new effort in the fiscal year 1972 Appropriations Bill, Congress expressed preference for a competitive design program and that the vehicle emerge cheaper and less complex than the previous two attempts, specifically criticizing the Shillelagh, autoloader, and hydropneumatic suspension. Therefore, the Army decided the new vehicle would be armed with a non-missile-firing gun, feature a four-man crew including a human loader, and run on a conventional suspension. A unit cost ceiling of $507,000 was established, necessitating future design compromises to ensure that this target could be met. The new tank was initially named XM815 but was redesignated XM1 by the end of 1973. Orr Kelly, 100. Sunell, 435-6. McNaugher, 33-4, 36.

The new tank was to emphasize crew survivability above all else, and tantalizing possibilities were offered by a new type of armor engineered by Dr. Gilbert Harvey at Britain's Fighting Vehicles Research and Development Establishment near Chobham.Orr Kelly, 108, 111-2. Hunnicutt, Abrams, 172, 177-8. Sunell, 436. Ogorkiewicz, Technology of Tanks, I: 51. Harvey's design was a form of nonexplosive reactive armor using nonmetallic and steel layers, and it was very effective against high-explosive antitank warheads as well as kinetic energy projectiles. However its protective properties needed to be balanced against its heavy physical weight. The issue was heady enough that on 27 September 1972 Creighton Abrams himself, now a four-star general and set to become Army Chief of Staff, made the decision to use an American version of this armor on the frontal arc of the tank, since in his opinion its promise of extra protection was more important than the weight penalty.Orr Kelly, 128. Sunell, 437. Sorely, Thunderbolt, 338-9. This armor is what gives the tank its characteristically slab-sided look. The crews of the new tank were also protected by the layout of its ammunition stowage, with the majority of the main gun ammunition in the turret bustle behind a bulkhead, a scheme that had been detailed at least as far back as early 1959 with combustible-case ammunition in mind. If the ammunition ignited, blowoff panels in the turret bustle's roof would vent the explosion out of the tank while the bulkhead doors protected the crew from danger.For early thoughts on compartmentalizing ammunition behind blast doors and using blowoff panels, see Technical Study and Proposed Development Program for a New Tank Main Armament System (U), 37-8.

105mm gun tank M1 Abrams

An armament competition for the new tank was held in the mid-1970s, and entrants included the 105mm M68 in use on the M60; a British 110mm rifle; and a 120mm smoothbore gun manufactured by the German firm Rheinmetall, the lineage of which could be traced to a US Army 120mm smoothbore project called the Delta gun that was tested in the early-mid 1960s but abandoned due to the preference for gun-launchers. Test results indicated the M68 was still a dangerous weapon thanks to improved ammunition technology, but the 110mm gun was hampered in performance by using APDS vice APFSDS ammunition. It was decided that since the 120mm gun was full of growth potential, the Rheinmetall ordnance would eventually arm the tank, but the initial M1 tanks were armed with the old M68 since this gun would continue standardization with the majority of NATO's tank fleet; could fire more types of ammunition than the nascent 120mm; and would not impose delay or further expense on the fielding of the new tank, which it was feared would have the potential of scaring Congress into cancelling the entire project.Ogorkiewicz, Technology of Tanks, I: 52. McNaugher, 38, 40, 43-5, 51-55. Sunell, 445-7. Hunnicutt, Abrams, 162-3. There may have been some political pressure applied to the main gun choice: A number of US Army officers involved with the XM1 would rather have used the 105mm M68 until a new next-generation gun was designed, but the West Germans were looking for a financial quid pro quo for their potential purchase of American early warning aircraft, although this possibility was denied by Secretary of the Army Clifford Alexander. See Orr Kelly, 176-93, and McNaugher, 55-6. On the relationship between Rheinmetall's 120mm gun and the Delta gun, see Ogorkiewicz, Observer of Cold War Tank Development, 29.

105mm gun tank M1 Abrams

Chrysler and General Motors submitted proposals and pilot vehicles, and Chrysler's design was selected. Once fleshed out, the prototypes suffered from problems with track shedding as well as engine and transmission failures, but these were eventually solved.Orr Kelly, 162-8. Sunell, 450-1. Hunnicutt, Abrams, 201. Stone, 103-5. Stolarow, 1-2. After enduring an abortive competition with an austere version of the KPz Leopard 2--the tank West Germany created after the KPz70's cancellation--the XM1 entered low-rate initial production on 28 February 1980 and was named after General Abrams. Standardization as the M1 was awarded on 17 February 1981. The new tank's firepower was upgraded in 1985 when a 120mm gun equivalent to the Rheinmetall ordnance was finally adopted on the M1A1.Hunnicutt, Abrams, 202, 204. The Army asserted that the Leopard 2 was not as well-protected as the XM1 prototypes, would cost more, and would not be ready for production as quickly. There was some debate over the objectivity of the tests, but the chief German observer opined that the Leopard 2 was given a "fair and equitable" shake. See "Department Of Defense Consideration Of West Germany's Leopard As The Army's New Main Battle Tank," 6-11. McNaugher, 37-8, 53-63. For a German viewpoint on the competition, see Spielberger, From Half-Track to Leopard 2, 231-9. For the development of the Leopard 2, see Spielberger, From Half-Track to Leopard 2, 204, 214-44.

120mm gun tank M1A1 Abrams

Mobility was greatly increased from previous machines. Its novel and powerful AGT-1500 gas turbine engine conferred an advantage in acceleration over conventional diesels. Development of a gas turbine tank powerplant had been recommended as far back as 1949 when the Army Field Forces Advisory Panel on Armor had mentioned the type as a way to increase the horsepower/ton ratio of tanks then under design.Harmon et al., I: B, 7; I: B, Inclosure 1, 6. The AGT-1500 proved thirstier than anticipated, but advantages of gas turbines compared to diesel engines included less power needed for cooling, higher specific outputs, the ability to run on a larger range of fuels and to be started more easily in cold temperatures, less noise and weight, the possibility of requiring less maintenance, and no smoke emission. Also, the rotation of the turbine was conserved into further rotating motion, in contrast to the linear motion of reciprocating pistons which must be translated into rotation.Ogorkiewicz, Technology of Tanks, II: 260-1. Hunnicutt, Abrams, 174-5. Orr Kelly, 144-5. Chait, Lyons, and Long, 29. Günter H. Hohl, "Off-Road Vehicles (Wheeled and Tracked)," in Road and Off-Road Vehicle System Dynamics Handbook, Mastinu and Ploechl, eds., 436. Though the Germans experimentally fitted a gas turbine engine into a Jagdtiger before World War II was over, the British mounted one experimentally in a Conqueror in 1954, and the US Army had an experimental gas turbine-powered tank by 1961, the Soviets were the first to field a tank solely with such an engine when the T-80 entered service in 1976. See Ludvigsen, 205-7; Ogorkiewicz, Technology of Tanks, 259; Hunnicutt, Abrams, 108; Baryatinskiy, Main Battle Tank T-80, 7-11; Hull, Markov, and Zaloga, 142-5; and Koch, 62-3. The Swedes combined a gas turbine with a diesel engine to power their Strv 103, which came into service in 1967. See Ogorkiewicz, Technology of Tanks, 56-7, 262-3. The M1's power-to-weight ratio was 183% of the M60A3's while the Abrams's higher-performance suspension granted over 50% more wheel travel, a combination that added up to much greater agility than the earlier tank.Hunnicutt, Abrams, 303. Hunnicutt, Patton, 443. Ogorkiewicz, Technology of Tanks, II: 318.

The venerable M60, borne out of a failed replacement for the M48, itself endured two failed replacement programs and became the United States' de facto premier tank for twenty years at the height of the Cold War, eventually facing off against impressive Soviet vehicles coming online in the 1970s. In a duel against the contemporary enemy T-64 or T-72M tanks, the US Army Materiel Systems Analysis Agency estimated the M60A1 and M60A3 could suffer from disadvantages of approximately 40% and 30%, respectively.Gorman, 13-4. The M1 Abrams was introduced none too soon.

105mm gun tank M60A3(TTS)

Other Army vehicles were taking shape along with the M60's successor. The M114 was introduced in 1962 as a small armored command and reconnaissance vehicle. Once in service, the M114's front hull overhang caused difficulty when crossing ditches or descending or ascending steep banks. Eighty of the vehicles served briefly with the South Vietnamese, but by November 1964 these had been replaced by the M113 due to a combination of the cross-country mobility problems, reliability issues, insufficient engine power, a cramped interior, and low track durability. Because of these debits, the M114 would never serve with US forces in that theater. FMC Corporation had developed a smaller version of the M113A1 as an alternative command and reconnaissance vehicle, but the M114 beat it into production. Though not adopted by its home country, FMC's machine was accepted by the Netherlands and, after some modification, Canada, which dubbed it the Lynx. Hunnicutt, Bradley, 226, 233-9. Starry, Mounted Combat in Vietnam, 37-8. Viet, 294-5. Cameron, To Fight or Not to Fight?, 196-7. Haworth, 67.

Armored command and reconnaissance carrier M114

In 1966 the Army attempted to replace the unsuccessful M114, but the program was saddled from the start by debate over the very mechanism that scouts should use: were they to obtain information by stealth or by fighting? By October 1971, design proposals were being sought for an XM800 armored reconnaissance scout vehicle (ARSV). Both a six-wheeled articulated-hull concept and a tracked vehicle were built, the former was manufactured by Lockheed and called the XM800W and the latter by FMC and called the XM800T. The 20mm gun M139 and a three-man crew were common to both. Tests were performed against each other as well as both standard and modified versions of the M113A1, FMC's Lynx, the V-150 armored car, the British CVR(T) FV107 Scimitar, FMC's XR-311 wheeled vehicle, and a modified M551. The XM800T was preferred to the XM800W, but for reasons including that neither of the prototypes could best the M113A1's mobility, neither of the prototypes was deemed acceptable for service. The findings of the testing combined with increasing program costs to instigate the ARSV's cancellation in September 1974, after $39.8 million had been spent.Cameron, To Fight or Not to Fight?, 284-7. Hunnicutt, Bradley, 241-4. Haworth, 69-71. Urbina, 411-2. Donn A. Starry, "Reflections," in Camp Colt to Desert Storm, 554-5. Sorely, ed., Press On!, I: 71.

Light armored car V-150

The Army began looking for a replacement for the M113 APC a few scant years after its introduction. The West Germans had been using the Schützenpanzer (SPz) Lang HS.30 since the late 1950s; this vehicle was armed with a 20mm gun and--unlike American APCs--allowed the infantry squad to fight while mounted through rear roof hatches. American planners wanted to emulate these German tactics of aggressively using infantry carriers, which stretched back to World War II when the Panzergrenadiere used their Sd.Kfz.251 half-tracks as fighting vehicles rather than simply protected transport.Herbert, 50, 62-4. Culver and Feist, 18-9. Haworth, 39-42. Diane L. Urbina, "'Lethal beyond all expectations': The Bradley Fighting Vehicle," in Camp Colt to Desert Storm, 410. Trauschweizer, 203-4. Simpkin, Mechanized Infantry, 29. Carter, Forging the Shield, 326. In addition, mounted combat was thought to be required on a battlefield contaminated by nuclear, biological, and chemical (NBC) agents.Haworth, 45. The planned MBT70 project also seemed to necessitate a faster and more agile infantry vehicle that could keep up with the highly-mobile tank.Haworth, 43. Urbina, 404. Hunnicutt, Bradley, 274. Trauschweizer, 203. The Mechanized Infantry Combat Vehicle 1970 (MICV-70) program was therefore mooted in 1963, and was to produce a family of vehicles similar in concept to those manufactured on the basis of the M113. Since the MICV-70 was a long-term project that was predicted to debut in the next decade, work on an interim MICV-65 began in March 1964. Based automotively on the M107 and M110 self-propelled artillery vehicles, a prototype of the MICV-65, called XM701, was delivered by May the next year. Although testing contributed to the MICV-70 project, the XM701 did not enter service due to concerns over its heavy weight, its size which precluded transport by Air Force C-141 Starlifter cargo planes, and its inadequate mobility versus the MBT70.Hunnicutt, Bradley, 274-8. Haworth, 43-4. Urbina, 404-5. Trauschweizer, 166.

Concurrent with the XM701, work on the XM734 had begun by December 1965. This vehicle was essentially an M113 APC with firing ports and periscopes added to the passenger compartment and a new commander's cupola armed with two 7.62mm machine guns or a single 20mm gun. In 1967 the XM765 project was initiated, with the first delivery in early 1969. Similar to the XM734, the XM765 was an M113A1 modified with firing ports and a 20mm gun in the commander's cupola. These M113-based vehicles, however, lacked the agility to keep up with the anticipated MBT70, and were not adopted by the Army.Hunnicutt, Bradley, 256-62. Haworth, 33, 52-3.

Despite the numerous prototypes and programs emerging in the early 1960s, by the middle of the decade America's most potent infantry vehicle remained the machine gun-armed M113A1. The seriousness of this situation was driven home when the Soviets unveiled their new Boyevaya Mashina Pekhoty (BMP) in the 7 November 1967 October Revolution Parade.Haworth, 47. Koch, 107. Entering initial low-rate production the next year and full production in 1970, the BMP was much more heavily armed than previous APCs, with a one-man turret sporting both a 73mm main weapon and an antitank missile launcher. It was also fitted with firing ports and periscopes in the passenger compartment to allow for mounted combat in an NBC environment. Compared to the M113, the BMP was a major threat.Hull, Markov, and Zaloga, 243-9. Koch, 107, 113. Mid-1970s US Army analysis asserted that, in a European clash, BMPs would cause 34% of the casualties imposed on friendly systems. See Sorely, ed., Press On!, I: 329. Likewise, West Germany started production of the SPz Marder in 1969. Though deemed too heavy for US use and lacking amphibious capability, the Marder provided the Germans with a modern infantry fighting vehicle (IFV) that could keep up with their fast Leopard tanks. The US, however, was still trying to pound out a doctrine for its new infantry vehicle, and therefore as well the vehicle's basic characteristics.Haworth, 50-2. The adoption of the BMP also caused some spirited debate over mechanized infantry doctrine in the Soviet Army. See Simpkin, Mechanized Infantry, 34-8; Hull, Markov, and Zaloga, 249; and General Colonel Viktor A. Merimskiy, "The BMP in Combat," in The Soviet Art of War, 284-6. The very authority over mechanized infantry was also debated upon, with the Infantry and Armor Schools both claiming responsibility.Haworth, 29-30. Urbina, 410-1. Herbert, 39-41. In the end, mechanized infantry became Infantry's burden.

Due in part to delays imposed by the Vietnam War, the MICV-70 project failed to yield a prototype until 1974. This vehicle, called XM723, was much more mobile than the older APCs thanks to its powerful 450hp engine. Its personnel layout was virtually identical to the BMP's, with a small one-man 20mm gun turret, firing ports in the rear for its eight dismounts, and the vehicle commander situated in the left front of the hull behind the driver. Reliability issues, the feasibility of the one-man turret, and the high cost of the XM723 compared to the M113, however, caused much concern during development.Hunnicutt, Bradley, 278-81. Urbina, 411-8.

In late 1975 the MICV program was merged with the struggling scout vehicle requirement, which was still unfulfilled after the ARSV's cancellation. Though combining the infantry and cavalry missions into a single project added complication, the economic benefits of using a common vehicle for both tasks were impossible to resist.Haworth, 75. Urbina, 411. Cameron, To Fight or Not to Fight?, 287. Starry, "Reflections," 554. The new machine would be based on the XM723, but the one-man turret was replaced by the TOW Bushmaster armored turret, 2-man (TBAT-II). The XM723's 20mm gun was eclipsed by the Bushmaster 25mm chain gun, and a twin TOW antitank missile launcher was mounted on the turret's left side, giving each mechanized squad a heavy, long-range antitank weapon. The proliferation of antitank weapons was thought to be imperative since, after Vietnam, the US had returned its attention to facing off with the Soviet Union and its huge park of armored vehicles. The missile would bestow upon the MICV valuable standoff range if it happened upon enemy tanks, which would, after all, have been common on the battlefield, and thereby also both increase the survivability of and reduce the battle-induced stress on friendly tanks.A contemporary report asserted that the USSR fielded five times the number of tanks and three times the number of modern infantry vehicles as the US. See Gorman, 2. Sorely, ed., Press On!, I: 82, 237, 315. Moving the vehicle commander into the turret from his previous spot behind the driver increased efficiency and eased his duties. The Soviets came to a similar conclusion regarding crew configuration and armament: The BMP-2, introduced in August 1980, mounted a larger turret than its predecessor with the vehicle commander now stationed inside. It dispensed with the 73mm main weapon in favor of an autocannon, and retained an antitank missile launcher.Hull, Markov, and Zaloga, 252-5.

After further testing and modification were completed, the first acceptance of the new M2 IFV and M3 cavalry fighting vehicle (CFV) occurred in May 1981. The vehicles were set to be respectively named for General of the Army Omar Bradley and General Jacob Devers, but due to the similarity of the two types both were dubbed Bradley in October 1981.Hunnicutt, Bradley, 282-5. Urbina, 418-25. Haworth, 77-80. The Bradley fighting vehicle (BFV) was controversial in both its guises. The debate over reconnaissance by stealth or force was by no means over: some cavalry troopers railed against the large size and signature of the M3. Stealth advocates certainly had cause for concern here, since a Bradley is dimensionally larger than a Sherman tank. The infantry were also nonplussed with the technical complication of both the vehicle and its role--necessitating that an infantry squad leader essentially also become a tank commander--and a shift in focus away from traditional dismounted infantry training in favor of vehicle gunnery. Some saw the halving of dismount squad size compared to earlier APCs as marginalizing infantry's contribution to the combined arms battle in favor of yet more vehicle firepower that simply supplemented tanks rather than assisted the carried troops. In addition, the TBAT-II turret was not universally viewed as a bonus, as some infantry and cavalry alike claimed the missile added unnecessary complexity and distraction. Experience with the new IFVs led to changes such as separating the tasks of dismounted squad leader and vehicle commander and restructuring the squads to 9-man units taking up seats in more than one vehicle.Gibbons, 29-37. Coffey, 103-6, 110-4. St. Onge, 120-1, 143-5. Cameron, To Fight or Not to Fight?, 288. Haworth, 102, 114-5.

105mm gun tank M1 Abrams and infantry fighting vehicle M2 Bradley

Drama was also played out in the public and legislative spheres, notably due to Air Force Colonel James Burton who, in his position in the testing office on the Secretary of Defense's staff from 1984-1986, fought to have testing guidelines revised to have full-up live fire tests on combat-loaded vehicles. Details of the testing procedures drew such ire between Burton and the Army that the press and the legislature became involved in the matter, with the fate of the entire Bradley program hanging in the balance. Live fire tests on seventeen vehicles were eventually performed, and in 1986 and 1987 Congress passed laws requiring similar testing before the acceptance of any weapons systems, although the Pentagon eventually worked to have these repealed. The live fire tests resulted in rearrangement of the internal stowage of the -A2 BFV models and the installation of additional armor protection. Spall liners, which had been previously suggested but not used due to expense, were also mounted. The additional armor, however, covered all but the two rear firing ports on the IFV, essentially deleting one of the original requirements of the vehicle.For Burton's side of the issue, see Burton, 126-212, 233-8. Haworth, 128-32. Urbina, 427. "Operation Desert Storm: Early Performance Assessment of Bradley and Abrams," 10-1. Green and Brown, 109-14. Sheridan, 19-20. For a counterpoint to the reform movement, see Gole, 255-7.

Infantry fighting vehicle M2A2ODS Bradley

The Bradley had defenders as well. Its proponents cited its increased firepower, armor protection, and mobility over the alternative, the M113 APC.Haworth, 116-7. Urbina, 410. St. Onge, 119-20. Cameron, To Fight or Not to Fight?, 289. Sorely, ed., Press On!, I: 234, 241. Major General (Retired) Stan Sheridan, the first Bradley vehicle program manager, summed the live-fire testing controversy in early 1999: "When it was all said and done, the testing reconfirmed what we already knew to be the protection levels of the vehicle. ... One has to wonder, was the result that cost the Army a company of Bradleys worth the time and expense? I don’t know the answer, but I can say that the Army did not learn very much from this testing which it did not already know. But the protection afforded America’s soldiers by today’s A2 Bradley is superior to that of early production vehicles and may be responsible for saving soldiers’ lives."Sheridan, 20.

Deep-seated doctrinal questions sat at the heart of both the infantry and cavalry dispute over the Bradley. The infantry struggled with the very definition of an IFV. Infantry fighting vehicles are a hybrid design, bridging the gap between "battle taxi" armored personnel carriers and infantry-support tanks, and designing a vehicle and doctrine to fulfill this complex niche occupied the US Army for almost two decades. Likewise, performance of reconnaissance by stealth or by force has a pendular doctrinal cycle, and debate would have been engendered whether the cavalry version was a robust fighting vehicle or a smaller, sneakier machine.Cameron, To Fight or Not to Fight?, passim.

Cavalry fighting vehicle M3 Bradley

The Army became interested in a self-propelled multiple rocket launcher in the mid-1970s, with a requirement formally released in March 1974. Partly inspired by the Soviet Union's superiority in numbers of rocket launchers, contracts had been let by 1977 for a so-called general support rocket system for counterbattery and suppression of enemy air defenses. Partners were sought for the project, and after difficult negotiations the United Kingdom, France, and West Germany came on board. All four countries were monetarily involved in the development, and agreed that the system would be manufactured both in the US and Europe. Initially intended to use 210mm rockets, the diameter was increased to 227mm to enable the use of West Germany's AT2 antitank mine. A carrier vehicle based on the BFV was engineered, and prototype testing began in 1979. Standardized as the multiple-launch rocket system (MLRS) M270, production started early in 1982 with the first US Army unit formed in March 1983. The twelve submunition-containing rockets stowed on a single vehicle carried a weight of fire equal to 3.6 volleys from a 155mm howitzer battalion, and these rockets could be fired off in a minute's time, giving the launcher a good opportunity to exit the area ahead of enemy return fire. The three-man crew represented a significant savings over the self-propelled howitzers then in service. Besides the free-flight rockets, a ballistic missile called the Army tactical missile system (ATACMS) was also designed for the MLRS. The Army hoped to build nuclear as well as conventional versions of this missile, but Congressional action in 1983 denied the ATACMS a nuclear option.Dastrup, King of Battle, 293-4, 308. Dastrup, Modernizing the King of Battle, 11-2, 18, 22-3. Hunnicutt, Bradley, 310-3.

Multiple-launch rocket system M270

Besides improving its hardware, the Army also changed and refined how it fought, especially in the latter half of the Cold War. After its exit from Vietnam, the Army returned its attention to the defense of central Europe, where Warsaw Pact forces arrayed against NATO were not only numerically superior but increasingly technologically competent. In 1974 General Andrew Goodpaster, Supreme Allied Commander, Europe, noted that NATO was outnumbered by 10,000 tanks in Europe's Central Region.Trauschweizer, 198. The 1973 Yom Kippur War had graphically illustrated the growing lethality of modern weapons, leading to a reassessment of survivability on the battlefield. These factors, when combined with the throttling of America's defense budget following the Vietnam War and the Army's poor state of readiness at the time, led the Army's new Training and Doctrine Command (TRADOC) to begin work on an updated FM 100-5 doctrinal manual in 1974.Romjue, From Active Defense to AirLand Battle, 2-6. Doughty, 41. Herbert, 5-6, 29-31, 99-102. Richard M. Swain, "AirLand Battle," in Camp Colt to Desert Storm, 363-7. Leonhard, 130. Citino, 255-6. Stone, 46-7. House, 239. Trauschweizer, 194, 201-3. Brownlee and Mullen, 190-1. Gole, 237, 240, 254, 261, 263. Scales, 9-10.

Urged on and partially written by TRADOC commander General William DePuy, the resulting Active Defense concept espoused that unengaged defending units would maneuver to the flanks of a Soviet penetration and chip away at the attack until it was halted; concentration of firepower at the right place and time would result from the mobility conferred by armored vehicles and aircraft, with the tank being considered the primary weapon system. Indeed the Armor Center and School heavily influenced the new doctrine, and its commander, Major General Donn Starry, also had a hand in its writing. At the time of its publication in 1976, even more mobile and lethal vehicles and aircraft--the M1 tank, Bradley fighting vehicles, and AH-64 Apache and UH-60 Black Hawk helicopters--were expected to be fielded by the end of the decade. Bearing in mind the lethality of contemporary weapon systems and their potential to quickly wipe out entire units, Active Defense stressed winning the first battle. The published manual was definitely more practical than theoretical, listing required force ratios, characteristics of various weapon systems, and even typical German weather patterns.Romjue, From Active Defense to AirLand Battle, 5-11. Doughty, 41-6. Herbert, 7-9, 40-5, 47-50, 75, 81-5, 88, 92. Swain, 372-5. Leonhard, 131, 133. Citino, 256-7. Stone, 47. House, 239-40. Trauschweizer, 206-9. Gole, 250. Scales, 10-4. Sorely, ed., Press On!, I: 315.

Controversy accompanied Active Defense from its introduction. Critics asserted that it was too Eurocentric and tactical, focused on defensive attritional warfare that emphasized firepower over maneuver, paid no mind to enemy echelons following up the initial attack, ignored potential Soviet tactical changes, downplayed the psychology of warfare, and was too formulaic and mathematical. Debate also occurred over the feasibility of the lateral movements required of unengaged units and the treatment of these units as a de facto reserve instead of having a traditional subtracted reserve.Romjue, From Active Defense to AirLand Battle, 14-21. Doughty, 43-6. Herbert, 96-8. Swain, 377-9. Leonhard, 133-5. Citino, 257-60. Stone, 112. House, 240, 250-1. Trauschweizer, 210-3. Burton, 1-3, 52-4. Gole, 261-2. Scales, 14-5. Sorely, ed., Press On!, I: 295, 300, 303, 308, 310. Starry alleged that at least some of the criticism arose due to disgruntled officers from Fort Leavenworth, whose Combined Arms Center and Command and General Staff College's Department of Tactics were essentially excluded from the formation of the new manual despite having that responsibility. For the allegations, see Sorely, ed., Press On!, II: 1111-3, 1125-7; for the conflict between TRADOC and Leavenworth during the manual's writing, see Herbert, 51-9.

Because of these criticisms, General Starry, who had taken command of TRADOC in July 1977, was tasked in June 1979 by Lieutenant General Edward Meyer, Deputy Chief of Staff for Operations and Plans in the Department of the Army, with revising the Active Defense doctrine.Swain, 380. Romjue, From Active Defense to AirLand Battle, 30-2. Trauschweizer, 217-8. Meyer would become Army Chief of Staff that same month. While Starry and his staff did initially work on mere revision, they ended up writing an entirely new doctrine. This edition of FM 100-5, dubbed AirLand Battle and published in 1982, emphasized offensive combined arms warfare and tactical flexibility while eschewing the mathematical, formulaic precepts found in Active Defense. The idea of mission orders was used, with free-thinking subordinates making and executing their own decisions based on their commanders' intentions rather than simply following detailed instructions. Enemy follow-up echelons were to be specifically targeted before they could be brought to bear, disrupting the enemy's plans and momentum and thereby potentially lessening the chances that nuclear weapons would be needed to stop an enemy offensive. AirLand Battle was characterized by four concepts: initiative, depth, agility, and synchronization. Forces were intended to achieve and retain the initiative, be positioned in depth with relation to time and space, react to situations faster than the enemy, and synchronize combined arms so that an enemy's reaction to one maneuver would put him at risk from another.Swain, 384-5. Romjue, From Active Defense to AirLand Battle, 58-9, 67-73. Leonhard, 136, 166. Citino, 262-3. Stone, 113-5. House, 251-2. Trauschweizer, 221-6. Scales, 25-7, 106-8. Dastrup, Modernizing the King of Battle, 14. Rather than a new doctrine, Starry himself considered AirLand Battle an evolution of Active Defense that added the attack of follow-on echelons. See Sorely, ed., Press On!, II: 1289-90. The question of reserves was settled when TRADOC Deputy Commander Lieutenant General William Richardson mandated that, especially for brigade-size units and above, a traditional reserve be kept instead of using the lateral maneuvers of unengaged units as a reserve.Romjue, From Active Defense to AirLand Battle, 71. Swain, 388. The operational level of war, residing between the tactical and strategic levels, was codified in Army doctrine for the first time thanks to the influence of General Glenn Otis, who had assumed command of TRADOC in August 1981. In a 1986 revision, the corps's placement at this level and the division's concentration on the tactical level was reinforced and better explained, synchronization of deep and close battles was clarified, and offensive versus defensive operations was better proportioned.Romjue, From Active Defense to AirLand Battle, 61. Swain, 383, 387. Scales, 25-6. Romjue, The Army of Excellence, 86-7. Romjue, American Army Doctrine for the Post-Cold War, 20. For an argument that the codification of the operational level was a rediscovery instead of a new revelation for the US military, see Matheny, passim. Like Active Defense before it, however, AirLand Battle was not immune to criticism for allegedly still focusing on attrition instead of maneuver, having the desire for synchronization override initiative, and for placing too much emphasis on air and artillery interdiction at the expense of combined arms.Leonhard, 136-7, 160-4. Burton, 51-4. In addition, some critics, including Supreme Allied Commander Europe General Bernard Rogers, contended that the 1982 manual was overly aggressive or provoking.Sorely, ed., Press On!, II: 1270. On the other hand, Peter Campbell, 145-51, argues that AirLand Battle was still inherently defensive.

The Yom Kippur War and the increased lethality of the battlefield it portended affected Army organization in addition to doctrine. The potential strength of the new crop of weapon systems anticipated to be coming to the field in the mid-1970s and beyond cast doubts on whether the ROAD divisions still enabled commanders to adequately utilize their fighting potential. TRADOC began a Division Restructuring Study in 1976, with a new interim Division 86 heavy division structure being approved in late 1980. After reductions to meet end-strength personnel restrictions, by October 1983 the new armored division employed 19,260 men with six armor and four mechanized infantry battalions that were organic to three brigades instead of being attached for different missions as in the ROAD division. A 19,452-strong mechanized infantry division had five tank and five mechanized battalions. The tank battalions had a fourth tank company added compared to the old version, and the tank platoon was reduced to four from five machines. Three-tank platoons had been discussed, but were thought too brittle as losing a single vehicle would be devastating to that unit. Automotive difficulties the XM1 tank was experiencing in the late 1970s also influenced the move to the four-tank platoon as a hedge against potential mechanical casualties. Six 107mm mortars and a scout platoon of six CFVs were given to the battalion's headquarters and headquarters company. The mechanized battalion was made up of four companies of three platoons apiece, each made of three ten-man squads, yielding a total of fifty-five M2 Bradleys. An antitank company with twelve improved TOW vehicles, six 107mm mortars, and a reconnaissance platoon of six CFVs augmented the mechanized battalion. An air cavalry brigade including forty-eight attack helicopters was added, and the division artillery could count on seventy-two 155mm and sixteen 8" howitzers, and nine MLRS launchers. The new division was thought to bestow improved combined arms, better command and control, stronger air defense, more firepower forward, and a smaller soldier-to-leader ratio.Romjue, A History of Army 86, I: 1-4, 43, 111-6. Romjue, The Army of Excellence, 7-10, 13-4. Dastrup, King of Battle, 298-9. Dastrup, Modernizing the King of Battle, 15-6. Sorely, ed., Press On!, II: 1249, 1258. Starry, "Reflections," 555-6. Trauschweizer, 199.

Improved TOW vehicle M901

Remodeling the Army's heavy divisions to the Division 86 tables of organization began in 1982, but ultimately the plan proved untenable. A 1983 TRADOC study suggested that it would take 836,000 active personnel to fulfill the new tables, but the Army's strength ceiling of 780,000 was not anticipated to be raised throughout the 1980s. Army Chief of Staff General John A. Wickham, Jr., instructed TRADOC to look at ways of slimming down formations, including Division 86. As part of the Army of Excellence (AOE) program, in late 1983 decisions were taken to find manpower savings in part by reducing both the heavy division's mechanized infantry squad and 155mm howitzer crew to nine from ten men, and by allocating the division's 8" howitzers and Chaparral antiaircraft missiles to corps control. Artillery in National Guard heavy divisions would differ by having six-tube batteries instead of eight-tube batteries, and by retaining the 8" howitzer instead of receiving the MLRS. Unlike Division 86, the AOE heavy division found its focus restricted more towards the tactical level of war while the heavy corps was steered towards the operational level, a change that was more in line with AirLand Battle doctrine. By the time the revisions were complete, the armored and mechanized divisions were reduced to 16,924 and 17,203 personnel, respectively.Romjue, The Army of Excellence, 20-1, 35, 49-50, 54-5, 85-6, 90-1. Dastrup, Modernizing the King of Battle, 16.

Guided missile equipment carrier M730A2 Improved Chaparral

Marine Corps armor development also was not idle during the latter part of the twentieth century. The venerable LVTP5 family served throughout Vietnam, taking part in the majority of the Marines' sixty-two amphibious landings during that conflict.Croizat, 235. Estes, Marines Under Armor, 166. Its replacement, the LVTP7/AAVP7, entered service in 1971 after a long gestation period partly caused by scant funding; these budgetary woes also were a factor in the cancellation of the planned engineer and howitzer versions of the LVTP7.Croizat, 235. Hunnicutt, Bradley, 344. Estes, Marines Under Armor, 174. The death of the XM803 project, which the Marines hoped would replace their aging fleet of M48s, forced the Corps to instead acquire the M60A1 in 1974. Two years later, tank and amphibian battalions were given back to the divisions, reversing the 1957 decision that centralized heavy equipment with the Force Troops.Estes, Marines Under Armor, 174-5. By mid-1978, the tank battalion was composed of a headquarters and service company; four tank companies each with three five-tank platoons and a headquarters with a two-tank section; and an antitank company with a headquarters and three antitank platoons with 24 TOW missile launchers each.FMFM 9-1, 5-8.

LVTP7

The Marines had employed King armored cars in the early part of the twentieth century, and wheeled armor would make a comeback with them in the early 1980s. By the 1970s, a lightweight, fixed- or rotary wing-deployable vehicle was seen as becoming imperative with the Corps's role as a rapid reaction force, and the mobile, protected firepower it would provide was thought necessary to keep Marine infantry capable of performing maneuver warfare operations. To meet this requirement, an eight-wheeled version of General Motors Canada's version of the MOWAG Piranha was introduced to the Corps in 1983 as the light armored vehicle (LAV).Estes, Marines Under Armor, 181, 212. Hunnicutt, Armored Car, 221. Shepard, 1-4. A family of machines was produced on this chassis, including--in addition to the standard LAV-25 25mm gun turret vehicle--command, mortar, TOW missile, recovery, logistics, air defense, and electronic warfare vehicles.

LAV-25

During the vehicle's initial development, the Army had been interested in the LAV-25 if modified to carry ammunition or cargo in the rear instead of dismounts, and the program even got to the point of being designated the M1047. The legislature, however, eliminated money for the Army's 2,350 desired vehicles, forcing the Marine Corps to carry on with the project alone.Hunnicutt, Armored Car, 222. In December 1989, the Army exchanged some MLRSs with the Marines for sixteen LAV-25s in order to run tests on it as a rapidly deployable armor asset. The vehicles were organized into the scout platoon of 3-73 Armor, and in the end were preferred by the scouts and the scout platoon leader over the high-mobility multipurpose wheeled vehicles (HMMWVs) with which they were then equipped as well as over the M3 Bradley.Hyatt, 32-3. Cameron, To Fight or Not to Fight?, 306-7.

Cohesively integrating the reconnaissance and infantry support missions for the LAV crews turned into an arduous task for the Corps. This is handily illustrated by both the doctrine and name of the units working through three iterations within the first decade of their existence. Confounding factors included the cancellation of the planned assault gun LAV and the delayed fielding of the air defense variant, which forced revisions to the planned organizational tables. The LAV battalions initially suffered from an ambiguous mission set and identity, being used simply as land-based carriers and having to "borrow" infantry to fill the dismounted scout positions in their vehicles. It was not until the late 1980s that infantry was added permanently to the organization. Nomenclature was then changed to Light Armored Infantry (LAI) battalions, and fulfillment of traditional cavalry-type missions was envisioned. 1994 saw the LAI battalions renamed again to Light Armored Reconnaissance (LAR) battalions, reflecting the changed opinion that they would now be used primarily to perform reconnaissance, with security or economy of force missions possible as well.Estes, Marines Under Armor, 182, 187-8, 190. Hunnicutt, Armored Car, 250-2. Michaels, 3-4. Rottman, 6. Shepard, 5-9.

LAV-AD

America's post-Vietnam armed forces and facets of AirLand Battle were put to the test in order to eject invading Iraq from its neighbor Kuwait during Operation Desert Storm in early 1991. A multinational coalition army was built up over five months,Stephen A. Bourque, "The Hundred-Hour Thunderbolt: Armor in the Gulf War," in Camp Colt to Desert Storm, 502-3. Scales, 40-2, 46-54, 57-65, 69-79, 82-93, 97-9, 391-3. and a long air campaign decapitated the Iraqi armed forces. This aerial bombardment was biased against more strategic targets, however: only ~17% of air sorties targeted Iraqi army units in the field.John Sloan Brown, 144. Consequently, when engaged by coalition ground forces the Tawakalna Mechanized Division of Iraq's Republican Guard still possessed 70% of its tanks and 60% of its infantry vehicles; likewise, the Hammurabi Armored Division had more than 80% of its combat forces and the Medina Armored Division still fielded almost two complete armored brigades.Bourque, Jayhawk!, 364. Overall, approximately 85% of Iraq's armored vehicles in the theater survived coalition airpower.Pollack, 159.

The country's newest armored vehicles, especially the M1 tank and BFVs, overcame desert-related maintenance issues and were vindicated in the ensuing ground campaign. Army Chief of Staff General Carl Vuono instigated the in-theater swapping out of many older Bradleys for the new -A2 models as well as exchanging over a thousand M1 Abrams tanks for better armed and armored European-based M1A1s. This was accomplished despite reservations that US Central Command commander in chief General H. Norman Schwarzkopf, Jr., and the Army Staff initially shared about sending crews to battle in potentially unfamiliar vehicles. Some units earmarked for change did get to train on the new vehicles while still in the US, while others were not switched until the day before the ground offensive.Scales, 79-80. Bourque, "The Hundred-Hour Thunderbolt," 503. Bourque and Burdan, 23-5, 45-7. Bourque, Jayhawk!, 94-5. Vernon et al., 107, 132-6. Schubert and Kraus, general eds., 120. Once deployed, the engine air filters of the Abrams required cleaning after as little as 6 hours of desert operation, and daily even when the engine was not started. As a result, 2/2 Armored Cavalry Regiment, for example, went to battle with three times the normal stock of engine air filters. Crews also stressed over the high fuel consumption of the gas turbine engine, a matter compounded by problems with fuel pump reliability. Still, readiness rates for the Abrams and Bradleys were around 90% during the ground campaign. The -A2 BFVs designed in response to live-fire tests garnered praise from crews who felt safer in them than in the older models, but as in previous conflicts, extra ammunition was commonly carried, largely negating the benefits of the redrawn stowage arrangements.Stone, 104. Schubert and Kraus, general eds., 142. Vernon et al., 52. Macgregor, 36. The readiness rate figure is expanded from peacetime operations, though, as relatively minor failures that would normally deadline vehicles were ignored during combat. See "Operation Desert Storm: Early Performance Assessment of Bradley and Abrams," 3, 10, 12-4, 16-7, 22, 25-8.

Marine LAVs and tanks had trouble with the higher-quality fuel dispensed in the Kuwaiti theater, which cleaned their fuel tanks of sediment left by the previously used diesel and deposited it in fuel filters and injectors, clogging them.Michaels, 34-5. Gilbert, Marine Corps Tank Battles in the Middle East, 48-50. The Marine Corps initially deployed with their M60A1s, and due to their more vulnerable nature compared to the newer Abrams, these tanks were fitted with explosive reactive armor suites to increase their protection against shaped charge attack. Some M60A1s were handed in for M1A1s and small numbers of M60A3(TTS) tanks after the units were in country.Estes, Marines Under Armor, 185. Gilbert, Marine Corps Tank Battles in the Middle East, 49. Though not all factors directly correlate, the Army's and Marine Corps's decisions to transition to more modern vehicles while in theater, including some marines' relatively drastic change from the M60A1 to the M1A1, can be contrasted with the Army's reluctance to utilize 76mm gun medium tanks immediately before the Normandy invasion.

105mm gun tank M60A1

In action, American forces were better trained, better led, better able to communicate and utilize information, and fighting with better equipment than their opponents. This combination helped lead the coalition to an Iraqi defeat in under five days. As a counterpoint, there are veterans and historians who argue that in contrast to the spirit of AirLand Battle, some US senior commanders were overly timid and allowed little initiative in the lower ranks, and that planners were still focused on attrition instead of maneuver warfare.Bourque, "The Hundred-Hour Thunderbolt," 524. Donnelly and Naylor, 248-51. Trauschweizer, 228-9. Gole, 283. According to House, 269, Citino, 288-90, Scales, 360, Bourque, Jayhawk!, 456-7, and Stone, 124-7, it must be realized that conclusions drawn from the conflict will be unique due to the desert terrain, air supremacy enjoyed by the Coalition, lengthy buildup allowed to Coalition forces, numerous willing allies and host nations, and at times lackluster morale and performance of the Iraqi forces. For counterpoint examples, see Leonhard, 267-72; Hayden, 29-31; Macgregor, 209-18; and Burton, 243-52. Scales, 303, and John Sloan Brown, 120, attribute the caution and close control to concern for fratricide casualties. Also, some argue that air strikes were initially overly concerned with interdiction targets. See Morris; 12-3, Burton, 240-3; Bourque, Jayhawk!, 460; and House, 270-1.

Top

Post-Cold War: Focusing Anew

Since the Vietnam War, Army armored units had been prepared to take on the hordes of tanks possessed by the Soviet Union, and that country's collapse in December 1991 threw the entirety of America's armed forces into a semi-limbo state. With the evaporation of the Soviet threat, Army troop strength was drawn down from 786,000 to 500,000 by the summer of 1993, with the 3d Armored Division among the units deactivated after Desert Storm. In 1994 the 2d Armored Division was relegated to performing organizational experiments; in 1996 it was renamed the 4th Mechanized Infantry Division.Fontenot, Degen, and Tohn, 5. Donnelly, 6. Reardon and Charlston, 1. Romjue, American Army Doctrine for the Post-Cold War, 137. John Sloan Brown, 124, 144. Funding followed a similar track, with the Army's budget being cut by 38% between 1989 and 1995.John Sloan Brown, 124.

The Persian Gulf War of 1991 had proved that the doctrinal concepts, training, and equipment developed to defeat the Soviet armies were viable and effective against an opponent modeled after the Soviet Union, but the amount of time it took to build up the forces used to evict Iraq from Kuwait, and the effort required to keep those forces supplied, seemed prohibitive. Indeed, US forces nearly overburdened their logistic support, especially transportation services, before and during the fast-paced hundred-hour ground war. For example, despite theater fuel reserves actually increasing by more than 7% over the course of the ground campaign, the difficulty of dispensing supplies to front-line units saw the 1st and 3d Armored Divisions almost running dry by the end of the conflict."Operation Desert Storm: Early Performance Assessment of Bradley and Abrams," 31-2, 39-41. Stone, 146-7. Gudmundsson, 174-5, 216. Leonhard, 296-7. Vernon et al., 308. Scales, 375, 379. Bourque, Jayhawk!, 65-7, 83, 86-7, 89, 352. John Sloan Brown, 61-3. Schubert and Kraus, general eds., 159, 205. A lighter, more deployable force was therefore deemed necessary to respond to the type of threats forecasted for the future, with the Army reenvisioned as keeping fewer forward-deployed elements and instead projecting power kept mostly based in the United States.Romjue, American Army Doctrine for the Post-Cold War, 22, 28. Donnelly, 5-6. John Sloan Brown, 92-8. A new doctrine was unveiled in June 1993 to replace the Cold War AirLand Battle, and this edition of FM 100-5 reflected the unfolding strategic realities by including prominent chapters on force projection and operations other than war.Romjue, American Army Doctrine for the Post-Cold War, 119-20, 126-7. The next March, Army Chief of Staff General Gordon Sullivan initiated changes to meet these predicted requirements, calling the goal Force XXI; five months later, a TRADOC concept pamphlet on future land operations emphasized the desirability of strategic mobility, lightness, lethality, and survivability.Donnelly, 5-7. Romjue, American Army Doctrine for the Post-Cold War, 140.

The latter part of the twentieth century saw huge leaps occurring in the information technology field, and the Army sought to exploit the potential battlefield advantages of emerging systems. Increasing units' situational awareness had been a concern even since immediately after World War II, when the War Department Equipment Board had presciently suggested, "Each armored vehicle should have equipment which will enable it to continuously determine its position accurately and to fix the location of adjacent and supporting units. It should be able to communicate these data to higher and cooperating units."Stilwell et al., 92. Later studies found that up to 65% of voice radio messages were related to the positioning and progress of friendly units.Sorely, ed., Press On!, I: 649. Worryingly, by the time of Operation Desert Storm the lethality of modern weapons far outranged the resolution of gunners' and commanders' sights, and consequently about one-fourth of the American battle deaths suffered in that conflict were caused by fratricide.Burton, 250. John Sloan Brown, 61-2, 119-20.

Remedies started to appear with the fielding of the M1A2 Abrams. An intervehicular information system (IVIS) was provided that enabled tanks to digitally transmit text messages and data to one another and other friendly units. Also, the Force XXI Battle Command Brigade and Below (FBCB2) and Blue Force Tracker systems set up a tactical Internet that allowed the positions of friendly vehicles and already-identified enemies or obstacles to be shared with friendly forces real-time via satellite and shown on color touch-screen displays."Operation Desert Storm: Early Performance Assessment of Bradley and Abrams," 17-8, 23, 33-4. Scales, 302-3, 366-7. Green, M1 Abrams Tank, 51-2. Green and Brown, 52. Zwilling, Stryker IAV in Detail, Part One, 10-1. "Force XXI Battle Command, Brigade-and-Below (FBCB2)," <http://www.globalsecurity.org/military/systems/ground/fbcb2.htm>. Fontenot, Degen, and Tohn, 9-10, 63. While giving an unprecedented common picture of the battlefield, these systems also opened the possibility for higher headquarters to micromanage the fight down to the level of even the individual vehicle. It had taken almost half a century for the state of the art to achieve the War Department Equipment Board's desire of proliferating such a detailed and constantly-updating view of the field, and the potential of this technology was not lost on General Frederick M. Franks, Jr. Having himself faced the specter of fratricide when he commanded VII Corps in Operation Desert Storm, as TRADOC commander in 1994 he equated the new systems to the groundbreaking mechanization and radio experiments of the early part of the century.Romjue, American Army Doctrine for the Post-Cold War, 138. For examples of Franks's and VII Corps's concern for friendly fire in Operation Desert Storm, see Bourque, Jayhawk!, 251-2, 372, 395; and Scales, 287-9.

120mm gun tank M1A2 Abrams

The transformation initiated by the march toward Force XXI would take the Army from the so-called Legacy Force with its light and heavy dichotomy into an Interim Force structure and finally into an Objective Force. The object was to allow the Army to dispatch a brigade to any spot on the globe within ninety-six hours, a division within 120 hours, and five divisions within thirty days. The Objective Force was to be equipped by the Future Combat Systems (FCS), development of which was announced by Army Chief of Staff General Eric Shinseki in October 1999. The FCS was conceived as consisting of a family of vehicles, both crewed and unmanned, that could be configured for a variety of missions; the first units were expected to enter service in 2011, with fielding finished by 2032.Reardon and Charlston, 3. Donnelly, 10-2. John Sloan Brown, 195-8. DARPA, <http://www.darpa.mil/tto/programs/fcs.html>. Federation of American Scientists, <http://www.fas.org/man/dod-101/sys/land/fcs.htm>. Defense Advanced Research Projects Agency (DARPA), <http://www.darpa.mil/fcs/news/news_release.htm>. "Future Combat Systems (FCS)/Future Combat System (FCS)," <http://www.globalsecurity.org/military/systems/ground/fcs.htm>.

New medium-weight brigades were earmarked for the Interim Force, and an Interim Armored Vehicle (IAV) was sought for these formations. In November 2000, it was chosen to base the IAV on the eight-wheeled General Motors LAV III, and on 27 February 2002 the vehicle was named Stryker after two Medal of Honor recipients. The Stryker, intended to slot between light vehicles such as armored HMMWVs and heavy ones such as tanks and IFVs, was expanded into a family of vehicles including an infantry carrier armed with a .50 caliber machine gun or an automatic 40mm grenade launcher, a mobile gun system (MGS) sporting a 105mm gun, a self-propelled mortar carrier, a TOW missile launcher, a reconnaissance vehicle, an engineer vehicle, an ambulance, a fire support team vehicle, an NBC reconnaissance vehicle (NBCRV), and a command vehicle.Zwilling, Stryker IAV in Detail, Part One, 2-4. Rottman, 10-1. Ogorkiewicz, Tanks, 174-5. Triggs, <http://www.dtic.mil/armylink/news/Feb2002/​a20020228stryker022802.html>. Reardon and Charlston, 4, 9-11. John Sloan Brown, 203-4. Adding lightness to units had largely gained consensus by the time of the IAV's introduction: from 2000 to 2002, the percentage of officers polled who felt heavy forces would remain the Army's chief component in the new century dropped from 56 to 18.Peter Campbell, 191.

M1126 Stryker ICV

In order to meet the decree that the medium brigades be capable of deploying anywhere in the world in ninety-six hours, one of the IAV's requisites was that it be transportable in the C-130 Hercules, the most numerous cargo plane in the Air Force. Despite this mandate, eight of the ten Stryker variants as designed were too heavy to fly on a C-130; engineers had to find ways of making the vehicles lighter.Zwilling, Stryker IAV in Detail, Part One, 18. Rottman, 10, 13. Fontenot, Degen, and Tohn, 20-2, 408. Jack Kelly, <http://www.post-gazette.com/nation/20020320mobilenat4p4.asp>. Triggs, <http://www4.army.mil/ocpa/read.php?story_id_key=965>. Even when the Strykers made the target weight, flight distance and airfield restrictions still applied, especially if applique and reactive armor suites were added to the vehicles."Military Transformation: Fielding of Army's Stryker Vehicles is Under Way, but Expectations for Their Transportability by C-130 Aircraft Need to be Clarified," 4.

The new machines were grouped into Interim Brigade Combat Teams, renamed on 1 July 2002 to Stryker Brigade Combat Teams (SBCTs). With thought given from the start to fighting in built-up areas, the brigade consisted of a headquarters and headquarters company; three infantry battalions each made up of a headquarters and headquarters company, three rifle companies, and an antiarmor company; an engineer company; a military intelligence company; a signal company; an artillery battalion made of a headquarters and service battery, three four-tube towed 155mm howitzer batteries, and a target acquisition platoon; a reconnaissance, surveillance, and target acquisition squadron; and a support battalion. The rifle company had a headquarters section, three four-vehicle rifle platoons, a three-vehicle MGS platoon, a two-vehicle mortar platoon, a medical evacuation team, a sniper team, and a fire support team. Initially, the organization and makeup of the SBCT was in almost constant flux as lessons from active deployments were digested and enacted; also some Stryker variants like the MGS and NBCRV were slow to the field after experiencing engineering or other delays. The TOW missile launcher, for example, substituted in the MGS platoon until the latter was introduced.Zwilling, Stryker IAV in Detail, Part Two, 4-12. Rottman, 40-1. Reardon and Charlston, 4, 10, 13, 24. When combined with information systems like FBCB2, the high speed and tactical mobility of the new vehicles bestowed so much capability that the new SBCTs were thought to be able to control an area previously handled by a division.Reardon and Charlston, 68. Stryker deliveries began in May 2002, but the end-goal FCS endured restructurings and parings, with the manned vehicles being cancelled in June 2009, and the rest of the FCS program eventually becoming integrated into the Army Brigade Combat Team Modernization program.Reardon and Charlston, 11. Grant, <http://www.dodbuzz.com/2009/06/23/its-official-fcs-cancelled/>. Ogorkiewicz, Tanks, 176. The "interim" Stryker served on, outlasting the vehicle family intended from the beginning to replace it.

M1128 Stryker MGS

The artillery had been looking to modernize its self-propelled howitzers since the mid-1980s, and the Advanced Field Artillery System-Cannon was intended to enter service in the 1990s with more mobility, survivability, and lethality than the M109. Named the XM2001 Crusader, high-technology information systems and automation would reduce manpower requirements and increase the vehicle's accuracy, response time, and ability to quickly displace. To save costs, ammunition- and supply-carrying variants were planned, and it was proposed that the Crusader's engine could replace the fuel-intensive gas turbine in the Abrams tank. A liquid-propellant gun was conceived and prototyped, but development of the propellant caused such delays that the Crusader was changed to a solid propellant ordnance in 1996. After General Shinseki's requirements for deployability were unveiled, the Crusader's weight was cut from 55 tons (50,000kg) to 38-42 tons (34,000 to 38,000kg). Two billion dollars had been spent on the program by 2002, and it was anticipated that a further $9 billion would be required. Although General Shinseki reported that it would require $18-24 billion worth of other systems to match the Crusader's abilities, the vehicle was cancelled in mid-2002, with part of its funding going towards the ill-fated FCS. The M109, undergoing significant upgrades throughout its life, remains in frontline service, a position it has occupied since 1962.Dastrup, Modernizing the King of Battle, 20-1. Zaloga, M109 155mm Self-Propelled Howitzer, 33-4. John Sloan Brown, 229-30. "Crusader History," <https://www.globalsecurity.org/military/systems/ground/crusader-history1.htm>. "Crusader History," <https://www.globalsecurity.org/military/systems/ground/crusader-history2.htm>. "Crusader History," <https://www.globalsecurity.org/military/systems/ground/crusader-history3.htm>. "Crusader," <https://www.globalsecurity.org/military/systems/ground/crusader.htm>.

155mm self-propelled howitzer M109A6 Paladin

Organizational modularity, which would enhance the Army's transportability and responsiveness, became a goal to supplement the planned equipment upgrades. First broached by the 1994 TRADOC pamphlet and initially only concerning combat support units and echelons above division, in Shinseki's Objective Force the concept came to also encompass combat units. Expandable brigade-sized maneuver units of multiple standardized types would become the Army's focus rather than the division, and these maneuver units would be assigned to higher headquarters on an as-needed mission-oriented basis. Like the SBCT, technological improvements such as FBCB2 would allow the new maneuver units to be as capable as the larger formations being replaced, and to ease troop rotation it was possible to use the same amount of personnel to create more of the new maneuver units than the number of then-current brigades. Development occurred while the country was actively fighting in Iraq and Afghanistan, and the process was pushed through by General Peter J. Shoomaker, recalled from retirement in August 2003 to succeed Shinseki as Army Chief of Staff. By April 2005 the modular design had created three higher echelons to go along with the maneuver units. To get around the reluctance of soldiers to abandon the history and traditions of their current units, seen for example during the pentomic reorganization, the three higher echelons were assigned the lineages of existing and historical armies, corps, and divisions, respectively, while lineages of brigades were assigned to the maneuver units themselves. The new heavy brigade consisted of two maneuver battalions each composed of a headquarters and headquarters company, two armored companies, two mechanized infantry companies, and an engineer company; an armored reconnaissance squadron; a fires battalion with a headquarters and headquarters battery, two field artillery batteries, and a target acquisition platoon; a special troops battalion composed of headquarters troops, a signal company, and a military intelligence company; and a support battalion with medical, maintenance, distribution, and forward support companies. Additional units could be assigned to each echelon to tailor the force for the intended mission.Donnelly, 3, 7-16, 21, 43-6, 73-4, 77-8. Reardon and Charlston, 2-3. Romjue, American Army Doctrine for the Post-Cold War, 140-1. John Sloan Brown, 257-9, 301-5, 311-4.

A vehicle program that emerged from counterinsurgency operations in Iraq and Afghanistan in the early 2000s was the provision of mine resistant ambush protected vehicles (MRAPs). By mid-2003 improvised explosive devices (IEDs) had become the main threat to US troops in Iraq, and the sophistication of their construction and use would continue to improve. As a result late that year, the theater command, Combined Joint Task Force 7, restricted the use of unarmored vehicles. Commanders in the field started requesting mine-resistant vehicles in 2004, but acquisition was delayed due to reasons including an institutional bias against irregular warfare programs, an emphasis on prevention of IED attacks rather than protection of troops, a complex and bureaucratic Pentagon requirements and funding system, and a reluctance to spend a large amount of money on a vehicle type that would potentially not be needed once the counterinsurgency missions were over. Instead, ad hoc armor was developed for vehicles in country, and production of armor kits for vehicles used for patrols, escort, and logistical duties was accelerated in the US, with manufacturers even delaying commercial orders in order to quickly churn out the government requests. These kits were not without drawbacks, though: the additional 2,000-4,000lbs (900-1800kg) of weight imposed by armor kits for the HMMWV had deleterious effects on reliability and handling, for example. It was 2007 before the Pentagon took action to acquire vehicles specifically designed to resist mines and ambushes, and approximately 28,000 MRAPs of various types and sizes were eventually purchased by the Army and Marines. Once in service, MRAPs produced the lowest casualty rate of the armored vehicles in Iraq, including the Abrams tank.Lamb, Schmidt, and Fitzsimmons, 1, 3-6, 9-10, 12-38. Wright and Reese, 111-2, 314-6, 509-13, 516. Guardia, 5-7, 45-8. GlobalSecurity.org, "Mine Resistant Ambush Protected (MRAP) Vehicle Program," <http://www.globalsecurity.org/military/systems/ground/mrap.htm>. Cameron, To Fight or Not to Fight?, 499-500.

Mine resistant ambush protected vehicle M1224 MaxxPro

The Marines continued to accept the M1A1 after Operation Desert Storm, and the last of their aging M60A1s was phased out by 1996. Concurrently, the organization of the tank platoon was changed from five to four vehicles to help account for the added expense of the new machines.Estes, Marines Under Armor, 183-5. A replacement for the Marines' AAVP7 was being developed by General Dynamics Land Systems Division and was expected to enter low-rate production by 2010, a year before the fortieth anniversary of the AAVP7's entry into service. Called the Expeditionary Fighting Vehicle, the new amphibian was to utilize a planing hull to skim along the ocean's surface, making over-the-horizon assaults faster and therefore more viable.General Dynamics Land Systems (GDLS), <http://www.gdls.com/programs/efv.html>. United States Marine Corps, <http://www.efv.usmc.mil/>, <http://www.efv.usmc.mil/highlights.asp>. Croizat, 239. Hunnicutt, Bradley, 360-1. Due to budgetary concerns, though, the program was cancelled in January 2011.Amos, <http://www.defense.gov/releases/release.aspx?releaseid=14179>. In its stead, the Marines are looking to develop a cheaper amphibious combat vehicle as well as a wheeled armored personnel carrier; a service life extension program will keep the venerable AAVP7 in the field until the new vehicles are procured.Kuiper, <http://www.marines.mil/unit/mcbquantico/Pages/​2011/EFVoustedforlesscostlytriumvirate.aspx>. A further upgrade program will involve installing a stronger applique armor kit, a new engine and transmission, suspension enhancements, external fuel tanks, and blast-mitigating seating. Deliveries of the first of 392 vehicles to be so rebuilt occurred in 2017.Bacon, <http://www.marinecorpstimes.com/story/military/2016/01/29/marines-aging-amphibious-vehicle-fleet-get-better-armor-more-power/79487266/>.

AAVP7A1

Despite the turn of the century clamor for lightness and more rapid deployability, heavy forces still have an important place on the battlefield, even when faced with counterinsurgency duties. This was illustrated during Operation Iraqi Freedom, which began on 19 March 2003. Tanks and IFVs destroyed enemy armored vehicles both at long range in the desert and in point-blank urban environments, and they were also successful against dismounted and irregular forces in cramped city streets. Army armored forces conducted raids through the downtowns of An Najaf and Baghdad proving that, despite withering gauntlets of fire thrown out by both uniformed and paramilitary enemy forces, American ground units were powerful enough to maintain complete freedom of movement.Zucchino, 1-66, 102-260. Conroy with Martz, 3, 165-209. Lacey, 109, 175-7, 205-19, 229-57. Fontenot, Degen, and Tohn, 272-3, 336, 340-74. Wright and Reese, 333-5.

When the campaign transitioned to counterinsurgency work, the long range of their mounted optics, machine guns, and cannon allowed vehicles to accurately engage targets while remaining outside the enemy's ability to return fire. Abrams tanks were able to shrug off most IEDs and antitank rockets, and consequently led most advances since local intelligence about enemy forces was often lacking. When enemy troops fired on or ran from the leading tanks, closely-following Bradley IFVs would take the enemy under fire using their 25mm chain guns, which tended to cause less collateral damage than tank cannon. Indeed, sensitivity to damage was so acute in some operations that utilizing tank cannon could require permission from the battalion level, and even the BFVs' 25mm guns sometimes needed clearance from the company commander. Independent thermal sights for the commanders of M1A2s and the -A3 BFVs allowed these vehicles to operate in urban settings while buttoned, saving the commanders from having to expose themselves through their hatches to gain better situational awareness.Gordon and Pirnie, 86. Lacey, 25-6, 27-8, 46, 101. Green, War Stories of the Tankers, 270-1. Fontenot, Degen, and Tohn, xxix, 274. Cameron, To Fight or Not to Fight?, 455-8. Wright and Reese, 325, 334-5, 342, 353-4. Chiarelli, Michaelis, and Norman, 8-12. Gott, 97, 99, 105-6. Fontenot, Degen, and Tohn also provide some defense of the tactical intelligence situation; see 423-4. For clearances required to use main guns, see Chiarelli, Michaelis, and Norman, 9. New command systems such as FBCB2 had a positive impact on fratricide rates during these operations.Wright and Reese, 581. With these lessons learned, the Abrams tank is expected to serve with the Army until 2050.Williams, 4. To put that into perspective, it will make the Abrams seventy years old when it is retired. Conversely, under sixty-four years elapsed from the very first tank action in September 1916 to the M1's introduction in February 1980.

Infantry fighting vehicle M2A3 Bradley

Marine armor was active in the 2000s as well. In urban operations like in Fallujah, Iraq, in November 2004, tanks were used both as traditional infantry support and as leading units supported by marines emplaced on rooftops and inside flanking buildings.Gott, 101, 105. Dennis A. Lowe, "Employing Armor Against the Islamic State: The Inevitable Urban Combined Arms Fight," in Blood and Concrete, Dilegge et al, eds., 248. AAVP7s were used as ersatz infantry fighting vehicles in Iraq, but their thinner armor compared to the Bradley forced their carried marines to dismount earlier and more often than Army mechanized infantry.Gordon and Pirnie, 87. LAR battalions carved out another doctrinal niche when grouped together with supporting infantry, artillery, air, and other assets to perform deep missions as an operational maneuver group during Operation Iraqi Freedom in 2003 and in Afghanistan in 2009.Shepard, 18-22. Also in Afghanistan in the latter part of the 2000s, the Corps found tank fire to be more accurate than artillery or airstrikes and consequently to cause less unintended destruction. In that politically sensitive theater, accurate firepower was a definite advantage.Gilbert, Marine Corps Tank Battles in the Middle East, 250-2.

The focus of the Marine Corps's mission was changed by the 2018 National Defense Strategy from combating Middle Eastern terrorism towards conflict with peer-level opponents such as China or Russia, and with special emphasis on the Indo-Pacific region. This shift led Commandant General David H. Berger to push the USMC towards being a lighter and more responsive and specialized force with less activity overlap with the Army. In a plan called Force Design 2030, some of the Corps's capabilities such as long-range precision fires, air defense, and unmanned vehicles were reprioritized in importance. Since future budgets were presumed to be static, strengthening these assets would necessitate reducing or eliminating others, such as tanks, conventional artillery, light attack and assault support aviation, and combat service support. Beginning in July 2020, the Marine Corps began deactivating all of its seven tank companies, along with slashing sixteen of its twenty-one artillery batteries (while adding fourteen rocket artillery batteries to its current seven), decreasing the number of infantry battalions by three to twenty-one, eliminating bridging assets, and deactivating two assault amphibian companies. Three LAR companies were planned to be added, but in the initial proposal Berger indicated that yet more LAR organizational redesigns may be imminent: "I remain unconvinced that additional wheeled, manned armored ground reconnaissance units are the best and only answer – especially in the Indo-Pacific region." Thus the Marine Corps's history with the tank, begun with the formation of a platoon of M1917s on 5 December 1923 and written during almost a century's of conflicts in locations including Pacific islands, Korean mountains, Vietnamese jungles, and Middle Eastern deserts, would conclude.Berger, 2, 7-10. McLeary, <https://breakingdefense.com/2020/04/marine-commandant-less-a-second-land-army-more-light-amphib-ships/>. Harkins, <https://www.military.com/daily-news/2020/03/23/marines-shut-down-all-tank-units-cut-infantry-battalions-major-overhaul.html>. Snow, <https://www.marinecorpstimes.com/news/your-marine-corps/2020/04/01/top-marines-says-light-armored-reconnaissance-is-outmoded-on-future-battlefield/>. Quoted in Berger, 10. Estes, Marines Under Armor, 5.

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In Summary

The United States has employed armored vehicles for over a century and a half, and its men and machines have necessarily been involved in the largest conflicts of those hundred and fifty-plus years. Armies on both sides of the Civil War utilized locomotives and trains as the basis for armed and armored self-propelled platforms, but the internal combustion engine switched development emphasis to automobiles and armored cars in the early 1900s. After their successful debut in French- and British-built tanks in World War I, American armored troops endured almost two decades of forced stagnation in both thought and practice. After another round of European unrest prodded the country into cogent introspection as well as firm action on mechanization, its machines fought on all fronts with virtually all its Allies during World War II, and its crews successfully engaged the enemy's more potently-armed and thickly-armored tanks. Shortly after World War II, American medium tanks helped control the North Korean armored spearhead and later provided accurate infantry-supporting direct and indirect fire in the difficult Korean terrain. Armored vehicles were initially dismissed as being unnecessary in Vietnam, but their value was soon shown, and they became an important tool in the theater. Failed replacement programs kept the M60 tank in frontline service for two decades during the Cold War, while simultaneously a struggle ensued to give the country's first infantry fighting vehicle conceptual and physical form. A new generation of American armored vehicles proved its strength when tested during the 1991 Persian Gulf War, but the collapse of the USSR and the anticipated threat of low-intensity conflicts that would require lethal forces to quickly arrive at a distant scene have spurred a trend towards lighter, more deployable vehicles for the future. Heavy forces have demonstrated throughout subsequent conflicts in the Middle East that they are still survivable and decisive, though.

The power and complexity of fighting vehicles have increased tremendously since their inception, and today the US remains at the forefront of development. However, as illustrated by many conflicts since World War II, high-tech weapons systems are not the crux of a victorious military.Citino, 222-3. Bacevich, 150-3, 156. Half a decade before the appearance of the tank, Patton wrote, "[W]e children of a mechanical age are interested in and impressed by machines to such an extent that we forget that no machine is better than its operator..."Quoted in Blumenson, The Patton Papers 1885-1940, I: 242. That sentiment is no less apt now that the mechanical age has progressed to the information age, and now that the tank itself and mechanized forces as a whole have matured: without highly-trained and motivated personnel acting in accordance with innovative and sound doctrines, even the most technologically sophisticated fighting vehicles are transformed from terrible, swift swords into white war elephants.

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