halftracks

The M3 Gun Motor Carriage (GMC) was a United States Army tank destroyer equipped with one 75 mm gun and was produced by Autocar. After the fall of France, the U.S. Army decided to make a self-propelled artillery piece from the M1897A4 gun on the M3 chassis, which was designated the T12. After some improvement, it came into production as the M3 Gun Motor Carriage. However, the supply of M2A3 gun shields was insufficient for production needs, so a new gun shield was used. This was designated the M3A1 GMC.

The T12/M3 first served in the Philippines Campaign in 1942 with the Provisional Field Artillery Brigade in the anti-tank and the fire-support role. It then served in North Africa in tank destroyer battalions. It was used ineffectively in the Battle of Kasserine Pass and several other engagements, but was used with success in the Battle of El Guettar. It also served in the Allied invasion of Sicily, but was eventually superseded by the M10 tank destroyer. A total of 2,203 were produced, of which 1,361 were converted back into M3A1 half-tracks.

The M3 GMC also served in the Pacific theater, starting with the Battle of Saipan. It proved effective against the Japanese Type 95 Ha-Go and Type 97 Chi-Ha tanks. It later served in the Battle of Okinawa, the Battle of Peleliu and many other island battles.
https://en.wikipedia.org/wiki/M3_Gun_Motor_Carriage