The M1 Field Gun, also known as the M1 "Long Tom", was a field gun that was used by the United States during World War II.


The M1 could fire a 155 mm shell at a maximum range of up to 22 kilometers. Being a very heavy weapon, the M1 required vehicular transport such as by tractor or truck. The advantages of the M1 though were that it was very accurate at range and reliable in the field. The design itself was of French origin, coming from World War I. The American M1 however had several key modifications made, particularly to its breech and loading functionalities.

The total weight of the M1 was about 13,880 kilograms while its total length was 13.7 meters.[1] In order to achieve effective operation, the M1 required a crew of at least fifteen men. One of the more common issues with the M1 came with crew operation in which sometimes a gun crew would decide to use rounds with a supercharge propellant more often than the gun could withstand, therefore expediting the rate at which the barrel of the gun deteriorated.[2]


The first variant of the M1 was the M1A1 which first appeared in 1941 which modified the breech ring. As only twenty examples of M1 had been built at that time, the M1A1 became the new standard and thusly the rest of the "Long Tom" guns from then on were M1A1s. Similarly, the M1 carriage was updated to the new specification of M1A1 with new refurbishments. The M2 Field Gun was a variant that attempted to simplify the method by which the breech ring was attached. The M2 was finally standardized in 1945. Alongside the M2 was the M5 Limber Carriage which was designed to speed up the rate at which the gun could be set up. 


The M1 was developed throughout the 1920s and 30s, taking after its French inspiration, but could not be completed until 1938 due to lack of funds for the project. When the developments finally saw their way into American military arsenals, the M1 became well liked. In combat, the M1 proved to be one of the most important artillery weapons ever to see service during World War II. The first combat operation the gun did see was in 1942 during the North African Campaign. From there, it would go on to see combat in almost every theater, from the Pacific, to Europe, to the Mediterranean. In total, some 350 M1 Field Gun units had been produced during World War II. In fact, some M1s continue to serve in some countries today.[3]


  2. Zaloga, J. Steven. US Field Artillery of World War II. Osprey Publishing (2007), Page 22

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