M12 Gun Motor Carriage

155mm Gun Motor Carriage M12
M12 firing across the Moselle River in France, 1944.
Type	Self-propelled gun
Place of origin	United States
Service history
Wars	World War II
Production history
Designed	1942
No. built	100
Variants	Cargo Carrier M30
Specifications
Mass	26 tons
Length	6.73 m
Width	2.67 m
Height	2.7 m
Crew	6 (Commander, driver, (4x) gun crew)
Main armament	155mm M1917/18 M1 gun 10 rounds
Secondary armament	.50cal Browning M2 machinegun
Engine	Wright (Continental) R975 EC2 340 hp
Suspension	vertical volute spring
Operational range	220 km
Maximum speed	38 km/h (19 km/h off road)

The 155 mm Gun Motor Carriage M12 was a U.S. self-propelled gun developed during the Second World War. Only 100 were built; 60 in 1942 and a further 40 in 1943. It mounted a 155 mm gun M1917, M1917A1 or M1918 M1, depending upon availability, a weapon derived from the nearly identical French 155 mm GPF gun of World War I vintage. The M12 was built on the chassis of the M3 Lee tank (some sources claim that later M12s used the M4 Sherman chassis, but this might be a confusion with the M12's use of "Sherman-style" bogie trucks with trailing idlers). It had an armored driver's compartment, but the gun crew were located in an open topped area at the back of the vehicle. An earth spade (similar to a bulldozer blade) at the rear was employed to absorb recoil. This layout—large gun mounted in an open mount at the rear, with a spade—was the pattern adopted for many years by other heavy self-propelled artillery.

During 1943 the vehicles were used for training or put into storage. Before the invasion of France, 74 M12s were upgraded in preparation for combat operations. They were employed successfully throughout the campaign in NW-Europe. Although designed primarily for indirect fire, during assaults on heavy fortifications the M12s were sometimes employed in a direct-fire role.

Limited storage space meant that only 10 projectiles and propellant charges could be carried on the vehicle. Given this, a similar vehicle, but without the gun, was produced as the Cargo Carrier M30. This was designed to transport the gun crew and additional ammunition. In operational conditions the M12 and M30 would serve in pairs. The M30, which could carry 40 rounds of 155 mm ammunition, was armed with a .50-caliber Browning M2 machine gun.

T14/M30 cargo carrier

Surviving artifacts

• The sole surviving M12 GMC is displayed at the Fort Sill museum [1], it was stored at the United States Army Ordnance Museum in Aberdeen, Maryland, USA, before being transferred to Fort Sill in November 2010.

See also

• List of "M" series military vehicles
• G-numbers

References

• Leland Ness(2002)Janes World War II Tanks and Fighting Vehicles, Harper Collins, ISBN 0-00-711228-9
• TM 9-2300 military vehicles
• TM 9-751 operators
• TM 9-1750
• TM 9-1750B
• TM 9-1750D
• TM 9-1751
• SNL G158 parts catalog

Gun material

• TM 9-2300 standard artillery and fire control material
• TM 9-345 155-mm M1918MI [2]
• TM 9-1345
• SNL D36

External links

• World War II vehicles
• AFV database