The M12 Gun Motor Carriage is a self-propelled gun designed by the United States military during the Second World War. It saw only a limited production run of 100 vehicles, with 60 produced in 1942 and a further 40 in 1943. It mounted a 155mm gun, typically an M1917, M1971A1 or an M1918 M1, depending on the availability. The M12 was based on the chassis of an M3 Lee tank. It had an armored driver's compartment, but the gunner's position was uncovered and exposed. An earth spade (similar to a bulldozer blade) was placed on the rear to act as a means of absorbing the guns recoil. This layout was further used in later designs for many years onward.
During 1943, they were primarily used for training operations or put into storage. Before the Invasion of France, 74 M12 were upgraded in preparation for combat operations. It was used successfully throughout the campaign in Northwest Europe. Although designed for indirect fire, it was sometimes used for direct fire against fortifications.
A limitation of the M12 was that it could only carry 10 rounds of 155mm ammunition. With that in mind, a variant was produced called the Cargo Carrier M30. The M30 was armed only with an M2 Browning Machine Gun, but replaced it's gun space with a cargo space to store up to 40 rounds for the M12's gun and could carry the gun crew. In combat, it was intended that the M30 and M12 serve in pairs.
In game
It is your main objective in the first and third Aachen level. It is required to destroy several fortified German positions in the town. The player must protect the Gun Carriage from German Anti-Tank crews as they escort it through it's mission through town. If it is destroyed, the mission will fail.