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M12 Gun Motor Carriage

1942 SELF-PROPELLED ARTILLERY WORLD WAR 2

History of the M12 cannon frame

In December 1941, when the United States devoted its vast resources and manufacturing capabilities to the world war, it faced a shortage of all kinds of war materials - small arms, planes, warships, combat vehicles, and more. As a result, 1942 led to numerous internal programs in an effort to develop weapons of war against Axis fire in North Africa, the Pacific, and Europe.

One such project is the M12 Gun Motor Carriage, a chain-mounted self-propelled gun (SPG) platform with a massive 155mm barrel attached to the chassis of an existing M3 General Grant/General Lee medium tank.

The M3 medium tank (predecessor of the more famous M4 Sherman series) was developed in the second half of 1940, finally entering production in August 1941 and ending in December 1942 with 6,258 units delivered. This guy was a capable beast at the time, he had a powerful 75mm main gun and a turret-mounted 37mm gun and was defended by up to four men.

30 caliber machine gun. Power is provided by a 400 hp Continental Motors R975 EC2 engine (licensed Wright R-975 Whirlwind) mated to a synchronized drivetrain. Top road speed on ideal surfaces is 26 mph, and range is less than 120 miles.

In practice, the M3 proved to serve the burgeoning U.S. war effort and was in extensive combat service (Lend - lease to ensure it finds its way across two oceans). However, the design was lacking in several key respects, most notably the mounting of the 75mm main gun on the laterally limited broadside, most of which required turning the entire vehicle towards the front of the enemy when attacking - a Cumbersome and time-consuming process. A laborious process, to say the least.

Additionally, the M3 proved slow off-road, and its high configuration (due to its composite turret design) made it a cannon fodder for enemy gunners at horizon range. So, numbers permitting, the M3 went down in history with the M4.

Regardless, the M3's usable and proven chassis is now being chosen for other battlefield roles, making it a logistically friendly solution to war, as car parts can be shared across the production line as well as in repair settings. The M3's basic hull design has been completely rewritten for the role, including a new superstructure designed to protect against small arms fire and artillery jets. However, only the driver was completely encased in steel armor, while the gunner was housed in the rear open compartment with the main gun armament (large breech and room to maneuver the large 155mm shell).

The canvas tarpaulin can be attached to several support arms above the breech, but little else will protect the rifle group from the dangers of the modern battlefield. The crew of six included the driver, vehicle commander, several gunners and several ammunition dealers.

The dozer blade is mounted on the rear of the hull and lowered when firing to counteract the violent recoil inherent in the main gun.

Key to the design of the new SPG artillery platform was the choice of the 155mm M1917 series field gun. The M1917 is a tried-and-true commodity, and the U.S. Army has had an inventory of this weapon since its entry into World War I. Essentially a French 155mm GPF, the M1917 performed extremely well in the heyday of World War I, and once again it made logistical sense to attach an existing gun to an existing chassis.

The weapon is available in "M1917" and "M1917A1" flavors, also in "M1918 M1" form. Depending on the existing arsenal of these barrels, the new SPG vehicle can use any of the three available - all firing large 155mm HE rounds. A recoil mounting mechanism supports the gun on the chassis behind the center of the vehicle.

While crossing is limited, some elevations are possible. The M1917/M1918 series of guns were born as indirect field guns (rather than direct fire like anti-tank guns) and have proven to be used to deliver explosive devices to target areas. Self-defense is through a single.

Browning M2 50 Caliber Heavy Machine Gun - Suitable for fighting light armored vehicles, infantry and low altitude aircraft. Since such SPG platforms will operate behind the main line of advancement, this defense is considered adequate. In addition, all personal weapons carried by the crew can be carried with them. The new SPG vehicle is designated "M12" in the U.S.

Army inventory.

The M12 weighed 26 tons and was powered by a Continental R975 EC2 gasoline engine, the same as the M3 Grant/Lee series tanks. Top speed on ideal road is around 23 mph, and range is 135 miles, although off-road performance is significantly reduced.

The chassis was mounted on a vertical volute suspension system (VVSS) common to American tracked vehicles at the time, a vehicle arrangement that allowed the vehicle to keep up with other mechanized forces when needed.

In service, M12 production was extremely limited due to the timely arrival of more powerful SPG solutions. As a result, only about 100 vehicles were produced, many of which were initially used to train new gunners, drivers, and commandos in the art of battlefield management, while other systems were stored and unused. However, for the Normandy landings in northern France in mid-1944, some 74 M12 vehicles were ready to use additional equipment, and these systems eventually made their way into Europe as the advancing U.S.

Army moved through France. The M12 proved its worth in using the 155mm gun to hit specific target areas while being called upon to destroy enemy-controlled structures. At this time, the "M30 Cargo Carrier" - a modified vehicle similar to the M3 Grant/Lee design, albeit lacking the 155mm gun - was deployed alongside the M12 gun carrier, as the M12 hull's special ammunition carrier was limited to 10x 155 mm projectiles.

The M30 Ammunition Carrier adds an additional 40x155mm projectile to each pair of deployed M12 artillery systems.

Only one example of the M12 survives today (2013), under the care of Fort Sill, USA. According to the US Army's military designation at the time, the M12 received the US Army's official designation "155mm Artillery Powered Carriage".

Likewise, the M30 aircraft carrier is also known as the "Cargo Carrier M30".