M12 Gun Motor Carriage - EE.UU.: libros - historia y técnica

M12 Gun Motor Carriage - Rare Photographs from Wartime Archives

Although only 100 examples were produced, the 155mm Gun Motor Carriage M12 served with distinction as an infantry-support weapon and in particular as a bunker-buster during the U.S. assault on the Siegfried Line in the winter of 1944-45.

The ability to rapidly ready heavy artillery for firing lead to the development of the M12 155mm gun in 1941, based on the M3 Medium Tank chassis. The trial vehicle, built by Rock Island Arsenal, was designated T6.
To accommodate the large, rear mounted weapon - a French-made M1917 155mm gun, the engine was relocated forward to a position just behind the driving compartment. A hydraulically operated spade mounted at the rear of the vehicle, which was lowered during firing to anchor the vehicle against the recoil. When retracted into the travelling position it provided a seat for two of the six crewmen.

The production run was between September 1942 and March 1943, with a total of one hundred units being built. Though a few were used by training units, most were placed in storage until February 1944, when the first of 74 of them were shipped to Baldwin Locomotive Works to be improved based on further tests and usage in training. This work continued until May 1944.

Three slightly different WWI surplus weapons were mounted depending upon availability, the M1917, the M1917A1 and the M1918M1. The M1917 was French built, the M1918 was US built, and the M1917A1 had the French gun tube, and the US breech.

155-mm Gun Motor Carriage M12 and Cargo Carrier M30 - Technical Manual (TM9-751)

The 155-mm Gun Motor Carriage M12 was a U.S. self-propelled gun developed during the Second World War. Only 100 were built; sixty in 1942 and another forty in 1943.
The M12 was built on the chassis of the M3 Lee tank. 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 at the rear was employed to absorb recoil.

During 1943 the vehicles were used for training or put into storage. Before the invasion of France, seventy four M12s were upgraded in preparation for combat operations. They were employed successfully throughout the campaign in North-West 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 ten projectiles and propellant charges could be carried on the vehicle. Given this, a similar vehicle 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 forty rounds of 155-mm ammunition, was armed with a .50-caliber Browning M2 machine gun.

Created in 1944, this technical manual reveals a great deal about the M12's and M30's design and capabilities. Intended as a manual for those charged with operation and maintenance, it details many aspects of the M12's engine, cooling, power, suspension and other systems.
Originally labeled restricted, this manual was declassified long ago and is here reprinted in book form. Please note, this text was not produced in large numbers and this replica may have some pages that are substandard in quality. Care has been taken however to preserve the integrity of the text.