Multiple Gun Motor Carriage T28E11-5

T28E1: General
Date of first acceptance July 1942 Total acceptances 80
Manufacturer Autocar Co.
T28E1: Dimensions
Gun overhang forward 0" Front tread 64.5"
Rear tread 63.8"
Wheelbase 135.5"
T28E1: Armament
Type Mount Ammunition Traverse Elevation
37mm Gun M1A2 Behind cab 140 rounds 360°
+80° to 0°
Two .50cal M2 MG Coaxial to 37mm gun 3,400 rounds
(2,000 ready)
+80° to 0°
Sighting system M2E1
T28E1: Armor
Rolled face-hardened steel
Location Thickness Angle from vertical
Radiator louvres .25"
Windshield cover .50"
Sides .25"
Rear .25"
Hood top .25"
T28E1: Automotive
Engine White 160AX; 6 cylinder, 4 cycle, in-line gasoline
Horsepower Net: 147@3,000rpm Torque Net: 325 ft-lb@1,200rpm
Transmission Spicer 3461 constant mesh, 4 speeds forward, 1 reverse
Steering Steering wheel
T28E1: 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 Spring-loaded at rear of track On front wheels
T28E1: Track
Center guide band type
Width 12"
Pitch 4"
Pitches/track 58 Track ground contact length 46.75"
T28E1: Performance
Min turning diameter 59'

The T28E1 was based on the half-track personnel carrier M3. The rear armor was deleted, the fuel tanks were placed directly aft of the cab, and a gun mount for an automatic 37mm gun using the top portion of the 37mm gun carriage M3E1 and two water-cooled .50cal MGs was installed in the former passenger compartment. Elevation to the front could not be lower than +20° due to interference with the cab structure. Two thousand .50cal rounds were stowed around the gun mount in ten ammunition chests, with the remainder in a stowage compartment in the rear of the vehicle. Once in service, mechanics modified the elevation mechanism to prevent the 37mm ammunition clip from binding against the gun mount when it ejected with the mount at +15° or less; gun depression was also increased to -5°.




  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. Sola, Samuel, Vincent Bobkowski, and Kara Crocker. Weapon Mounts for Secondary Armament. Santa Monica, CA: G. O. Noville & Associates, Inc., April 1957.
  4. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  5. 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 15 Nov 2023.
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