M2A1 105 MM Howitzer

Originally designated as the 105-mm howitzer M2A1 on carriage M2, the M101 howitzer was the light howitzer of choice for Allied forces during World War II. Like many World War II howitzers, the M101 traces its developmental genesis to the post-World War I era. Following the close of hostilities during the First World War, research on German 105-mm howitzers developed several candidates of ordnance. A series of continued research continued various trails, carriages, and tubes before finally settling on a combination that was not only extremely accurate, but extremely powerful. Thus, by 1940, the M2A1 was born.

Designed to be durable and stable, the M2A1 rapidly gained notoriety among the Western Allies for extremely accurate and devastating firepower. It also required very little maintenance, being able to withstand great amounts of stress over time.

From 1941 to 1953, Rock Island Arsenal and Kia Machine Tool Company produced over 10,000 of the howitzers. Around 8,500 of those were produced during World War II, with the remainder being produced until 1953. Many were distributed via Lend-Lease. Many others were exported to NATO nations following the end of the war. The M2A1 continued to see American use during Korea and Vietnam.

The M2A1 was redesignated the M101 in 1962 following the standardization of artillery designations.

The M101 could deploy multiple ammunition types to include high explosive (HE), incendiary, armor piercing (AP), smoke, and chemical shells. Many of these rounds were used across multiple howitzer systems of the same caliber. The howitzer is also used in anti-avalanche measures to generate controlled collapses that can prevent risks to life, agriculture, and property.

Because of its versatility, the M101 has been the basis for numerous studies and experimental systems. Examples include the M2A2 Terra-Star and the XM124. Most experimental designs were produced by Rock Island Arsenal from 1959 to 1973.

Despite being retired from U.S. service following the Vietnam War, many other nations continue to use the M101. In some U.S. formations, the M101 is sometimes still used as a salute gun. Most recently, the weapon has been used in the Russo-Ukrainian War.