From a small
combat experience gained in the U.S. Army during World War I, the U.S. War Department concluded that there was the need to be armed with analogue French 155-mm gun GPF. Ballistic Data its trunk is considered the best among similar tools belligerent countries, and therefore that the main part of the gun was borrowed unchanged American designers to create their own artillery system.
Works, which began in 1920, was completed in late 30s manufacture guns, officially designated 155-mm gun carriage M1 to M1. Gun had two-axle carriage and sliding frame. For a long barrel 45 caliber gun nicknamed Long Tom (Tom Long), a nickname then switched to self-propelled M40 based on Sherman tank. This ACS was launched into production in 1943 with one towed guns and artillery pieces combat debut in July 1944, after the Allied landings in Normandy. In late 1944, has been updated to gun M1 and M1A1 received the designation, later replaced by a shorter name M2.
In the 50s, during the reorganization of the U.S. Army, many older, but still in the arsenal guns identified other indices, M2 and M59 renamed. Long Tom gun was used to fight the counter-battery in all military conflicts involving the United States. The disadvantage of guns considered its low mobility due to the large size and weight. In ammunition 155-mm gun shots were separate kartuznogo loader with explosive, smoke and chemical shells. Besides the U.S., Long Tom gun was in the armies of many other countries around the world.