The M6 Gun Motor Carriage was the first American tank destroyer of WWII - a 37mm antitank gun (basically identical to the M3 gun) mounted on the back of a Dodge 3/4 ton weapons carrier. A large armor shield protected the gun crew from small arm fire, but the vehicle was otherwise highly exposed. The truck was powered by a flathead 6-cylinder engine producing 99 horsepower, and had a top speed of 55 mph. The gun was effective and modern in the late 1930s when its design process began, but was underpowered and insufficient by the time the M6 first saw action in 1942/3 in Tunisia.

Not many complete M6 carriages remain in existence today, as they were replaced quickly after their poor showing in North Africa. Most had the guns removed and were converted back into utility trucks, while some were used by the Free French forces and some saw use in the Pacific theater (where the underpowered gun was less of a concern).