The design incorporated a 57 mm gun M1, a US production of the British Ordnance QF 6 pounder, mounted on an M3 half-track.

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.

Britain retained 30 and the remainder were taken by the US; except for one kept by the U.S. Army, these British and American vehicles were converted back to standard M3 half-tracks.

The Soviets called it the SU-57 (Samokhodnaya ustanovka 57); under this designation it served in Operation Bagration and other fighting on the Eastern Front during World War II.

With a fuel capacity of 60 US gallons (230 L), it had a range of 150 miles (240 km), and was powered by a 128 hp (95 kW)[2] White 160AX, 386 in3 (6,330 cc),[3] 6-cylinder gasoline engine with a compression ratio of 6:3:1.

[6][a] The requirement was met by emplacing a 57 mm gun M1 – the U.S. production version of the British Ordnance QF 6-pounder – in the rear of an M3 half-track.

The tubular pedestal was soon replaced with a conical structure that was designated the "57 mm gun mount T5".

[7][10] The original design used a gun shield taken from the T44 57 mm gun motor carriage, but after the first tests were complete, a new shield was designed with face-hardened steel 5/8 inch thick on the front and 1/4 inch thick on the sides and top.

By the time the vehicles arrived in the theater in the summer of 1943, the British had already won the war in the Western Desert.

The Polish People's Army used T48s assigned to the 7th Self-Propelled Artillery Battery to support Soviet attacks into Germany and Poland.