57mm Gun Motor Carriage T481-12

T48: General
Date of first acceptance December 1942 Total acceptances 962
(281 converted to M3A1 personnel carriers)
Manufacturer Diamond T Motor Car Co. Crew
5 men:
  • Gun commander in rear
  • Gunner in rear
  • Driver in cab left
  • Assistant driver in cab right
  • Loader in rear
T48: Dimensions
Combat weight 19,000lbs
8,600kg		 Height over gun shield 90"
230cm
Length with roller 252.63"
641.68cm		 Gun overhang forward 0"
Width over side armor 77.25"
196.2cm		 Fire height 72"
180cm
Front tread 64.5"
164cm		 Rear tread 63.8"
162cm
Wheelbase 135.5"
344.2cm		 Ground clearance 11.2"
28.4cm
Ground pressure, tires 33psi
2.3kg/cm²
T48: Armament
Type Mount Ammunition Traverse Elevation
57mm Gun M1 Mount T5 99 rounds
(20 ready)		 55°
(27.5° left and right;
manual)		 +15° to -5°
(manual)
Aiming equipment
Telescope M18 for gunner
T48: Armor
Assembly
Bolting
Hull
Rolled face-hardened steel
Location Thickness Angle from vertical
Gun shield front .625"
1.59cm		 26°
Gun shield sides .25"
.64cm		 0°
Gun shield top .25"
.64cm		 75°
Radiator louvres .25"
.64cm		 26°
Windshield cover .50"
1.3cm		 25°
Sides .25"
.64cm		 0°
Rear .25"
.64cm		 0°
Hood top .25"
.64cm		 83°
T48: Automotive
Engine White 160AX; 6 cylinder, 4 cycle, in-line gasoline
Horsepower Net: 147@3,000rpm Torque Net: 325 ft-lb@1,200rpm Fuel capacity 60gal
230L
Transmission Spicer 3461 constant mesh, 4 speeds forward, 1 reverse
Steering Steering wheel
Brakes Hydraulic (Hydrovac)
T48: Suspension
Type Road wheels Track return rollers
Front: Semi-elliptic longitudinal leaf spring
Rear: Vertical volute spring		 Front: Steel ventilated disc
Rear: 1 bogie/track;
4 dual/bogie		 1 dual/track
Drive sprockets Idlers Shock absorbers
18-tooth front drive Adjustable fixed at rear of track On front wheels
T48: Track
T68E1
Center guide band type
Width 12"
30cm		 Pitch 4"
10cm		 Pitches/track 58 Track ground contact length 46.75"
118.7cm
T48: Performance
Max level road speed 45mph
72kph		 Max grade 60%
Angle of approach 33° Angle of departure 45°
Max vertical obstacle 12"
30cm		 Min turning diameter 59'
18m
Max fording depth 32"
81cm		 Cruising range ~200mi, roads
~320km, roads

The T48 was mainly intended for shipment to allies under Lend-Lease, and the 57mm gun M1 was an American version of the British long-barreled 6 pounder Mark V. The T48 was set up much like the M3 75mm GMC, with the gun in the passenger compartment firing forward and a notch in the downward-folding armored windshield cover. The roof of the driving compartment was removed, and a travel lock was attached to the hood. The T5 gun mount placed the top of the 57mm gun carriage M1 on top of a conical mount. The T48 was fitted with the small, demountable headlights after the 75mm GMC M3's large fender-mounted lights were damaged by muzzle blasts. The T48's hood was also reinforced to prevent damage from the firing of the gun. An ammunition rack was situated at the rear of the passenger compartment. Twenty ready rounds could be stowed in the top portion of the rack behind a hinged cover, and forty rounds in their fiberboard tubes could be stowed below the ready rack.

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References

  1. Hunnicutt, R.P. Half-Track: A History of American Semi-tracked Vehicles. Navato, CA: Presidio Press, 2001. Reprinted from Half-Track, R.P. Hunnicutt ©2001, available from Presidio Press, 505B San Martin Drive, Suite 160, Navato, CA 94945.
  2. Doyle, David. U.S. Half-tracks: The Development and Deployment of the U.S. Army's Half-track Based Multiple Gun Motor Carriages and Gun Motor Carriages, Part two. Ed. Pat Stansell. Delray Beach, FL: The Ampersand Publishing Group, Inc., 2016.
  3. FM 23-75 57-mm Gun M1. Washington, DC: War Department, 15 June 1944.
  4. TM 9-2800 Standard Military Motor Vehicles. Washington, DC: War Department, 1 September 1943.
  5. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  6. Chamberlain, Peter, and Chris Ellis. British and American Tanks of World War Two. Frome, England: Cassell & Co., 2000.
  7. Catalogue of Standard Ordnance Items, volume II. 2nd ed. 1944. Washington, D.C.: Office of the Chief of Ordnance, Technical Division, 1944.
  8. Hogg, Ian V. The Greenhill Armoured Fighting Vehicles Data Book. London: Greenhill Books, 2000.
  9. SNL G-102 Service Parts Catalog for Cars, Half-track, M2 and M2A1; Carriers, Personnel, Half-track, M3 and M3A1; Carriages, Motor, 75-mm Gun, M3 and M3A1; Carriers, 81-mm Mortar, Half-track, M4 and M4A1; Carrier, 81-mm Mortar, Half-track, M21; Carriage, Motor, Multiple Gun, M13; Carriages, Motor, Multiple Gun, M15 and M15A1; Carriage, Motor, Multiple Gun, M16; Carriage, Motor, 105-mm Howitzer, T19; Carriage, Motor, 75-mm Howitzer, T30; Carriage, Motor, 57-mm Gun, T48. 30 September 1943.
  10. Tank Data, vol. 2. Aberdeen Proving Ground, MD: US Army Ordnance School, July 1958.
  11. Siemers, Cary. "USA's Half Track Gun Motor/Mortar Carriages." World War II Tanks & Vehicles and Advanced Squad Leader. 4 July 2001. 13 August 2001 <http://www.siemers.com/wwii/USA/GunMotorCarriage.htm>.
  12. Track Data. Warren, MI: Track & Suspension Laboratory, Components Research and Development Laboratories, Research & Engineering Directorate, US Army Tank-Automotive Center, 23 June 1965.
Last updated 6 Jan 2024.
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© Copyright 2001-24 Chris Conners