M110 howitzer

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.

General characteristics
According to the operators manual, the M110's typical rate of fire was 3 rounds per two minutes when operated at maximum speed, and 1 round per 2 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 2 to 4 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 massive 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.

History
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 5th Battalion 18th Field Artillery from Ft. Sill, OK. served in Desert Storm with the M110A2 Howitzer. Most of 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. 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.

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 M110s or 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.

Projectiles

 * 1) M14 Dummy
 * 2) M106 HE
 * 3) M650 HE Rocket Assist Projectile (RAP)
 * 4) M509 ICM
 * 5) M404 ICM anti-personnel (airburst)
 * 6) M426 agent GB Sarin
 * 7) M422A1 W33 (nuclear weapon)
 * 8) W79 (nuclear artillery shell)

Users

 * 🇧🇪 Belgian Army 11 M110A2 between 1972 and 1993.
 * 🇪🇬 Egyptian Army Received 144 M110A2 as aid in 1996.
 * 🇩🇪 German Army M110A2 until 1993.
 * 🇬🇷 Greek Army 145 M110-A2 to be scrapped.
 * 🇮🇷 Islamic Republic of Iran Army.
 * 🇮🇱 Israeli Army 36 M110.
 * 🇮🇹 Italian Army M110A2, phased out by 1998.
 * 🇯🇵 Japan Ground Self-Defense Force as 91 M110A2.
 * 🇯🇴 Jordanian Armed Forces as M110A2.
 * 🇰🇷 Republic of Korea Army M110 until 2008.
 * 🇲🇦 Moroccan Army as M110A2.
 * 🇵🇰 Pakistan Army 60 in service as of 2010.
 * 🇧🇭 Royal Bahraini Army 13 M110A2 from Netherlands delivered in 1994, 25 M110A2 from US delivered in 1996.
 * 🇳🇱 Royal Netherlands Army M110A1 and M110A2, replaced by the M109 in the 1990s
 * 🇪🇸 Spanish Army as 64 M110A2, deployed in divisional fire support regiments until 2009.
 * 🇹🇼 Republic of China Army 60 as M110A2.
 * 🇹🇷 Turkish Army, currently phasing out 219 M110A2 in favor of T-155 Fırtına
 * British Army as M110A2 firing high explosive and nuclear shells only. (The FV433 Abbot SPG, the M109A2, and the M110A1 were replaced by the AS-90 in the early-mid-1990s.) Used in combat in Operation Granby/Gulf War.
 * 🇺🇸 US Army & United States Marine Corps.
 * Army of the Republic of Vietnam.