3" Gun Motor Carriage M51-6

M5: General
Total acceptances 1
Manufacturer Cleveland Tractor Co. Crew
4 men:
  • Commander
  • Gunner
  • Loader
  • Driver
M5: Dimensions
Combat weight 22,570lbs
Height 74"
Length 181"
Width 99"
Tread 78"
Ground clearance 16"
Ground pressure, zero penetration 9.2psi
M5: Armament
Type Mount Ammunition Traverse Elevation
3" Gun M6 On rear of chassis 33 rounds 34°
(11° left and 23° right;
+15° to -8°
Aiming equipment
Sight M6 or telescope M41 for gunner
M5: Armor
Location Thickness Angle from vertical
Gun shield .375"-.5"
Drivers' stations .5"
M5: Automotive
Engine Hercules DWX DFS; 6 cylinder, supercharged, inline diesel
Horsepower 150@2,800rpm Torque 316 lb-ft@1,950rpm Fuel capacity 62gal
Transmission Clark model 275 VO-1, 5 speeds
Steering Controlled differential, steering levers
M5: Suspension
Type Road wheels Track return rollers
Vertical volute spring 2 bogies/track;
2 dual wheels/bogie
2 dual/track
Drive sprockets Idlers
Front drive Dual trailing adjustable at rear of track
M5: Track
Center guide, reinforced rubber with replaceable rubber shoes
Width 14"
Ground contact length 95"
M5: Performance
Max level road speed 38mph
Max grade 40%
Max vertical obstacle 12"
Min turning diameter 34'
Max fording depht 30"
Cruising range 192mi

The 3" GMC M5 was based on the Cleveland Tractor Company's (Cletrac) seven-ton high speed tractor MG-2. The 3" gun M6 was ballistically identical to the 3" gun M7 later found on the heavy tank M6 and 3" GMC M10. The only armor on the vehicle was provided by the gun shield and two small shields in front of the driver's and assistant driver's/gunner's positions; these men sat in front of the rear-mounted gun during travel and therefore would have had no protection from the gun shield. With the gunner's seat in place, traverse to the right was limited to 18°. The project was begun in December 1940, and the vehicle was standardized in January 1942 with intentions to procure 1,580 carriages. A protracted development period--during which the vehicle's estimated weight increased by almost 50%--as well as problems with reliability, structural integrity, small ammunition load, and track failures led to the cancellation of the project in August 1942 before production had actually started. At that point, work on the M10 was far enough along that the first production examples of this much more successful vehicle were accepted the next month.



  1. Hunnicutt, R.P. Stuart: A History of the American Light Tank, volume 1. Navato, CA: Presidio Press, 1992. Reprinted with permission from Stuart, R.P. Hunnicutt ©1992, available from Presidio Press, 505B San Martin Drive, Suite 160, Navato, CA 94945.
  2. Moran, Nicholas. Can Openers: The Development of American Anti-Tank Gun Motor Carriages. Brattleboro, VT: Echo Point Books & Media, 2017.
  3. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  4. Baily, Charles M. Faint Praise: American Tanks and Tank Destroyers during World War II. Hamden, CT: The Shoe String Press, Inc., 1983.
  5. Tank Data, vol. 2. Aberdeen Proving Ground, MD: US Army Ordnance School, Jul 1958.
  6. Gill, Lonnie. Tank Destroyer Forces--WWII. Paducah, KY: Turner Publishing Co., 1992.
Last updated 20 Dec 2023.
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