The T48 57 mm Gun Motor Carriage was a self-propelled anti-tank gun produced by the Diamond T company in 1943 for the United States. The design incorporated a 57 mm gun M1, a US production of the British Ordnance QF 6 pounder, mounted on an M3 Half-track. A total of 962 vehicles were produced from 1942 to 1943. It had originally been planned that Britain would receive all of the examples produced through Lend-Lease, intending to use them in the Western Desert, but by the time they arrived the campaign was over. Additionally, the purpose-built M10 tank destroyer, armed with a 3-inch gun (and later a 17-pounder gun in British service) had begun to enter production. As a result, the British transferred 650 half-tracks to the Soviet Union under the Soviet Aid Program.
The vehicle consists of a 6 Pounder anti-tank gun mounted in the rear compartment of an M3 Half-track, and has capacity for three players. The main armament is operated from the second seat, with the gunner behind a frontal gunshield but otherwise exposed to small arms fire from the rear or high explosive splash damage. The gun has unlimited ammunition and the same damage statistics as the stationary 6 Pounder, but is limited in traverse meaning it is the responsibility of the driver to orientate the vehicle hull towards any intended target. A third hull gunner operates a Bren Gun from inside the vehicle.
This variant of the M3 possesses similar health, armor and handling characteristics of the transport version, meaning it is far weaker than any other cannon-armed armored fighting vehicle in the game and cannot match a regular tank in a straightforward slugging match. Although spawning into the vehicle give the driver the Tanker kit, the T48 lacks notable features of a tank such as Specializations, Smokescreens or Emergency Repair, but is not subject to the same requirements as a tank, meaning it does not need to resupply ammunition and can self-repair itself to full health. The T48 GMC is therefore best used long range while from a defensive position, after which it can utilize its high speed to relocate and thus avoid direct confrontations.