M12 155mm Artillery Battery

The M12 Gun Motor Carriage was a Self propelled gun that saw service in the United States army. It is most notable for mounting the monstrous US 155mm Howitzer on a mobile platform, making it one of the largest SPG in the war.

IRL

The M12 first started out as an idea to make use of the outdated Lee/Grant chassis. The Germans themselves had already been doing this, so the Yanks figured that maybe the Krauts were onto something. Therefore, they took the chassis, reworked it, and shoved the biggest fuckoff gun they could find in their arsenal, and thus begins the awesomeness that is the M12.

The M12 saw limited production in 1942 and 1943, with only 100 models built, and for the early part of the war they served as training vehicles for crews that would go on to operate the M7 Priest SPGs. However, the allure of a mobile 155mm Howitzer could not be resisted, and were deployed to France as soon as they were upgraded for combat operations.

The M12 served with some manner of distinction, though their numbers were quite limited. Due to the lack of adequate storage within the vehicle, a ammo carrier was developed to serve alongside the M12, called the M30. The M30 also had an M2 .50cal machine gun to make up for the lack of Machine guns on the M12 itself. M12s earned a reputation for being a preferred method for breaching enemy strongholds, and more often than not the vehicle was called in to directly fire on enemy defensive positions.