The M12 155mm GMC was based on the chassis of the M3 “Lee” medium tank. It was one of the earliest US self-propelled weapons developed during the war. It mounted a 155mm M1917 or M1918M1 gun.

The turret and superstructure were removed, the engine was moved forward to behind the driving compartment, and the 155mm gun was mounted at the rear of the vehicle. Fitted to the rear of the hull was a heavy spade, which was lowered to the ground before firing to absorb recoil. The driver’s compartment was the only part of the vehicle fitted with a roof. M12 was built with the three-piece final drive and differential housing and almost all had heavy-duty suspension bogies with the track return roller to the rear of the bogie.

The two 155mm guns were virtually identical, and used the same ammunition and propellant. The M1917 was a French gun, the M1918M1 was American, and when the M1917 was fitted with the breech ring of the M1918M1, the new weapon was designated as M1917A1.

In 1942 about 100 M12 155mm GMCs (Gun Motor Carriage) were built, but were put into storage before entering combat. In 1943, as part of the preparations for the invasion of Normandy, 74 were refurbished and put back into service. It proved to be a powerful and effective weapon providing heavy fire support to fast moving armoured columns.

The crew manned the gun from the rear, in a similar manner to servicing a ground mounted artillery piece. It was sometime put into service in direct fire support where the formidable gun could easily demolish bunkers and other fortifications. When the 155mm rounds were fitted with concrete piercing fuses they could penetrate up to 6’/180cm of concrete before exploding. It could also make quick work of enemy tanks, though the crew were vulnerable to return fire making this an option of last resort.

The Artillery Board asked for more M12s, but this was not possible since the supply of M1917 and M1918M1 155mm guns was exhausted.


M12 155mm GMC

Armament: 155mm gun, M1917 or M1918
Armour: 10mm - 25mm
Engine: Continental, R975-C1, 9cyl. radial, air-cooled, gas, 400hp
Speed: 24 mph
Range: 140 miles
Crew: 6
Weight: 29.5 tons



  • Four M12 155mm GMC
  • Four loading crew
  • one command team
  • one observer team
  • one jeep
  • one decal sheet



SKU 26550
Barcode # 4872

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