M110 howitzer

8" M110 self-propelled howitzer
M110A2 of the Japan Ground Self-Defense Force in 2007
Type	Self-propelled artillery
Place of origin	United States
Service history
Wars	Vietnam War Iran–Iraq War 1982 Lebanon War Gulf War
Production history
Manufacturer	General Motors Corp. (transmission)
Specifications
Weight	28.3 metric tons (62,390 lb)
Length	10.8 m (35 ft 5 in)
Width	3.1 m (10 ft 2 in)
Height	3.1 m (10 ft 2 in)
Crew	13 (driver, 2 gunners, 2 loaders, (8 support crew–other vehicle))
Armor	13 mm (.51 in)
Main armament	8" (203 mm) M201A1 howitzer 2 rounds
Secondary armament	none
Engine	Detroit Diesel 8V71T, 8-cylinder, 2-stroke, turbocharged diesel 405 hp (302 kW)
Suspension	Torsion bar
Operational range	523 km (325 mi)
Speed	54.7 km/h (30 mph)

The 8 inch (203 mm) M110 self-propelled howitzer was the largest available self-propelled howitzer in the United States Army's inventory. Consisting of a M115 203 mm howitzer installed on a purpose built chassis, 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.

According to the operator's manual, the M110's typical rate of fire was three rounds per two minutes when operated at maximum speed, and one round per two minutes with sustained fire. The M110 featured a hydraulically operated rammer to automatically chamber the 200+ pound projectile. These rammers were prone to breakdown and generally slowed operation of the gun, because the rammers required crews to completely lower the massive barrel before using it. Highly trained and motivated U.S. Army crews could achieve two to four rounds per minute by using the hand-operated manual rammer, which was essentially a heavy steel pole with a hard rubber pad on one end. Using the manual rammer was physically demanding, but crews were not required to lower the barrels nearly as much as with the hydraulic rammer.

The M110's range varied from 16,800 meters to approximately 25,000 meters when firing standard projectiles, and up to 30,000 meters when firing rocket-assisted projectiles.

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 was used as the basis for their howitzer. The M110A2 is the latest version with a double muzzle brake, the earlier A1 version had a plain muzzle. It first entered service with the U.S. Army in 1963. It was used in the Vietnam War by the United States Army, and in Operation Desert Shield and Operation Desert Storm by Romeo Battery 5th Battalion 10th Marines, and the British Army. The 5th Battalion 18th Field Artillery served in Desert Storm with the M110A2 Howitzer. Most of the U.S. Army and USMC relied on the M109 series 155 millimeter gun systems during this conflict; sending remaining M110s to reserve or National Guard units. These units then took possession of M109s as they returned from service in the Gulf. M110s were still in service with the 3/92 FA (USAR) and running fire missions at Camp Atterbury as late as the summer of 1994.