57mm Gun Motor Carriage T481-8

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
8600kg
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
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)
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
Gun shield top .25"
.64cm
75°
Radiator louvres .25"
.64cm
26°
Windshield cover .50"
1.3cm
25°
Sides .25"
.64cm
Rear .25"
.64cm
Hood top .25"
.64cm
83°
T48: Automotive
Engine White 160AX; 6 cylinder, 4 cycle, in-line gasoline
Horsepower Net: 147@3000rpm Torque Net: 325 ft-lb@1200rpm Fuel capacity 60gal
230L
Transmission Spicer 3461 constant mesh, 4 speeds forward, 1 reverse
Steering Steering wheel
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
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%
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. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  4. Chamberlain, Peter, and Chris Ellis. British and American Tanks of World War Two. Frome, England: Cassell & Co., 2000.
  5. Hogg, Ian V. The Greenhill Armoured Fighting Vehicles Data Book. London: Greenhill Books, 2000.
  6. Standard Nomenclature List G-102. 30 Sep 1943.
  7. Tank Data, vol. 2. Aberdeen Proving Ground, MD: US Army Ordnance School, Jul 1958.
  8. Siemers, Cary. "USA's Half Track Gun Motor/Mortar Carriages." World War II Tanks & Vehicles and Advanced Squad Leader. 4 Jul 2001. 13 Aug 2001 <http://www.siemers.com/wwii/USA/GunMotorCarriage.htm>.

Last updated 3 Apr 2016.
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© Copyright 2001-16 Chris Conners