M114 155 mm howitzer

The M114 is a towed howitzer developed and used by the United States Army. It was first produced in 1942 as a medium artillery piece under the designation of 155 mm Howitzer M1. It saw service with the US Army during World War II, the Korean War, and the Vietnam War, before being replaced by the M198 howitzer.

The gun was also used by the armed forces of many nations. The M114A1 remains in service in some countries.

Development
After the end of the First World War a board later labeled the Westervelt Board was convened to assess the artillery experience of the combatant powers and map out future directions for the US Army artillery. The conclusion of the board vis-a-vis corps (heavy field) artillery was that an ideal heavy howitzer should have range of at least 16,000 yards and allow the elevation of 65° (as opposed to the existing World War I-era M-1918 155 mm howitzer's, a license-built French Canon de 155 C modèle 1917 Schneider, 11.5 km and +42° 20' respectively). Board also recommended that the new 155-mm howitzer and the new 4.7 in gun share all the carriage, even if it compromises both designs.

The M1920 carriage resulting from this requirements was of the split-trail type with pneumatic equilibrators, permitting a total traverse of 60°. Unfortunately, it "gave considerable trouble due to the persistent failure of the top carriage" on the firing tests. In 1923–1925 the design was modified with the top carriage reinforced, with the result standardized as M1925. However, it was never built in steel, because after the evaluation of a wooden model the project was abandoned. Instead, two new carriages were developed and built in the following years, which were designated T1 (photos) and T1E1. All of them had the same ballistics (perhaps even the same gun body), with maximal range of 16,390 yds, and were undergoing tests in early 1930s. By 1934, the US Army was concerned about the arising high-speed towing requirements not satisfied by the plain bearings and solid rubber ties.

In 1939 the development began anew, by spring 1941 the first specimen was ready to be test-fired and immediately after passing them it was standardized on 15 May 1941 as Howitzer M1 on the Carriage M1. The howitzer itself differed from the older model by a lengthened barrel of 20 calibers and a new breech mechanism. Uniquely it was the sole 'slow-cone' interrupted screw mechanism to enter US service after 1920.

The ballistics of the adopted variant ended up being very similar to French Canon de 155 L modèle 1918 Schneider gun.

Carriage variants
The carriage was also used by the 4.5 inch Gun M-1. It went through a number of minor changes over time. The original Warner electric brakes were replaced by Westinghouse air brakes on the M1A1. Both the M1 and M1A1 carriages used a mid-axle firing pedestal that was extended by a ratchet mechanism. The M1A2 replaced the ratchet with a screw-jack system and also modified the traveling lock. The M1A1E1 carriage was intended for use in jungle and muddy terrain and replaced the wheels of the M1A1 with a free-wheeling tracked suspension, but the project was terminated after V-J day without having reached production. The T-9 and T-10 carriages were projects using low-grade steel alloys that were canceled when no longer needed. The T-16 was a light-weight carriage using high-grade steel that was estimated to save some 1200 lb; work began in July 1945 and continued after the war, although nothing seems to have come from it.

A mid-1960s variant was the 155mm XM123 & M123A1 auxiliary-propelled howitzers. The XM123 was produced by American Machine and Foundry and outfitted with two 20 horsepower air-cooled engines produced by Consolidated Diesel Corporation, driver's seat, steering wheel, and guide wheel on the left trail, allowing it to be more rapidly emplaced when detached from the prime mover, while the XM123A1 provided a single 20 horsepower motor with electric steering. The extra weight on the left trail displaced the howitzer after each round was fired, requiring it to be realigned, and the project was abandoned. The concept was copied from the Soviet 85mm SD-44 auxiliary-propelled antitank gun developed in 1954 and used by airborne forces.

Self-propelled mounts
The howitzer was experimentally mounted on a lengthened chassis of the M5 light tank. The resulting vehicle received the designation 155 mm Howitzer Motor Carriage T64. A single prototype was built before the T64 project was abandoned in favor of T64E1, based on the M24 Chaffee light tank chassis. This was eventually adopted as the M41 Howitzer Motor Carriage and saw action in the Korean War. Towards the end of the Korean War the US Army replaced the M41 self-propelled howitzer with the M44 self-propelled howitzer.

Ammunition
The gun fires separate-loading, bagged charge ammunition, with up to seven different propelling charges, from 1 (the smallest) to 7 (the largest). Muzzle velocity, range and penetration in the tables below are for maximum charge in form of complete M4A1 propelling charge.







Former operators

 * 🇮🇹 Italy
 * 🇯🇵 Japan 220 total, a small number were produced domestically as Type 58. All retired.
 * 🇳🇱 Netherlands
 * 🇪🇸 Spain
 * 🇺🇸 United States
 * 🇪🇸 Spain
 * 🇺🇸 United States