The 8 inch (203 mm) Self-Propelled Howitzer M110 was the largest available self-propelled howitzer in the United States Army’s inventory. It was deployed in division artillery in general support battalions and in separate corps- and Army-level battalions. Missions include general support, counter-battery fire, and suppression of enemy air defense systems. The M110 was exported to a number of countries and remains in service with three NATO armies — the Greek, Spanish and Turkish.
The M110’s rate of fire can reach 3 rounds per two minutes when at maximum, and 1 round per 2 minutes with sustained fire. Its range varies from 16,800 m to 30,000 m when equipped with a rocket-assisted projectile.
The heritage of the M110 goes back to the British 8 inch (203 mm) howitzer of World War I.
A number of these were used by the American Forces and the design used as the basis for their howitzer. The M110A2 is the latest version with double muzzle brake, the earlier A1 version had a plain muzzle. It first entered service with the US Army in 1963. It has been used in the Vietnam War by the United States Army, and in Operation Desert Shield and Operation Desert Storm by the British Army. The US Army and USMC relied on the M109 series 155 millimeter gun systems during this conflict; sending remaining M110s to Reserve/National Guard units. These units then took possession of M109s as they returned from service in the Gulf. The last round fired from an M110 took place at Ft. Drum NY on 23 June 1991.
The gun system has been retired from US Army service; howitzers above 155 mm caliber are no longer effective as technology has closed the range and firepower gap, and heavier weapon systems require more resources to operate. Gun barrels from retired M110s were initially used as the outer casing in the manufacture of the GBU-28 bunker buster bomb.
The M110A2s were made from refitted M107 175mm SP Guns (Hunnicutt).
At the end of the Cold War under U.S. Division Plan 86, all armored and mechanized infantry divisions included a battalion of heavy artillery that included two batteries of M110A2 8″ SP howitzers with 6 guns each for a total of 12 guns, plus one battery of nine MLRS rocket artillery.