M-12 155mm Gun Motor Carriage

The M-12 Gun Motor Carriage mounted the M1 155mm gun on a modified M3 Lee medium tank chassis. The M12 was the first 155mm self-propelled artillery produced for the U.S. military, with 100 units delivered in March 1943. They were initially ignored, but were refurbished in late 1943 and proved to be very effective in Europe in the battles following the D-Day landings in France, June 1944. The refurbishment included use of the heavier suspension of the M4 Sherman tank with the rear-mounted return roller, a small shield was installed on the gun mount and the co-driver's hatch was removed.

The M-12 consisted of the M-3 tank chassis with the engine moved forward to accomodate the M4 mount for the 155mm gun. The gun was the M1917, M1917A1, M1918 or M1, very similar guns derived from the French 155mm GPF (Grande Puissance, Filloux), also the same as was used for the towed 155mm "Long Tom".

The rear of the hull was fitted with a spade/blade that could be lowered to the ground to anchor the rearward movement from the shock of the gun firing. The M30 Cargo Carrier was provided as an ammo carrier vehicle for the M-12. It was the same as an M-12 but without the 155mm gun.

The manufacturer was Pressed Steel Car Company of Pittsburgh, PA with Baldwin Locomotive in Philadelphia, PA performing refurbishment.

Specifications of the M-40 155mm Gun Motor Carriage

M12 155mm self-propelled gun firing across the Moselle River in France, 1944.

M12 155mm self-propelled gun, from TM 9-3305, Principles of Artillery Weapons.