M110 howitzer

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 lb (91 kg)+ 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. Well trained and motivated crews could achieve two to four rounds per minute for short periods by using the manual rammer, 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 as much as with the hydraulic rammer.

The M110's range varied from 10.4 mi (16.8 km) to approximately 16 mi (25 km) when firing standard projectiles, and up to 19 mi (30 km) when firing rocket-assisted projectiles.^[4]

The M110 howitzer first entered service with the U.S. Army in 1963 and was used in the Vietnam War by the United States Army. Later versions were used in the Gulf War - Operation Desert Shield and Operation Desert Storm by Tango Battery 5th Battalion 11th Marines, and the British Army's 32nd Regiment Royal Artillery.^[5]

In 1977 the upgraded M110A1 entered service, featuring a longer M201 series barrel which gave it an increased range. The final version, the M110A2, added a double muzzle brake. The M110A2s were made from refitted M110s or M107 175 mm self-propelled guns.^[6] The 2nd Battalion 18th Field Artillery (U.S. Army), which inactivated in 1994 at Fort Sill, Oklahoma, and the 5th Battalion 18th Field Artillery served in Desert Storm with the M110A2, as did the 142nd Field Artillery Brigade (Arkansas Army National Guard) and 1st Battalion 181st Field Artillery (Tennessee Army National Guard). Most of the U.S. Army and Marine Corps relied on M109 series 155-millimeter howitzer systems during this conflict, sending remaining M110s to reserve or National Guard units. These units then took possession of M109s as they returned from combat operations. M110s were still in service with the 3rd Battalion 92nd Field Artillery (US Army Reserve) and running fire missions at Camp Atterbury as late as the summer of 1994.^[7]

The howitzer has been retired from U.S. Army service, replaced by the M270 multiple launch rocket system.

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 SP howitzers with six guns each for a total of 12 guns, plus one battery of nine M270s.^{[citation needed]}

Israel used M110s along with M107s during the Yom Kippur War against Egyptian and Syrian forces. Later, in 1982, Israel used M110 systems against the Palestine Liberation Organization and their Lebanese allies with deadly effect during the Siege of Beirut as part of Operation Peace for Galilee.^{[citation needed]}

Iran used its M110s during its offensives against Iraq in the Iran–Iraq War.^{[citation needed]}

The Turkish Armed Forces have used M110A2 systems against the Kurdistan Workers' Party since the 1990s, as well as in the Turkish military intervention in Syria, mainly against the People's Protection Units.^{[citation needed]}

In the 1990-1991 Gulf War, the M110 had an unusual role. The GBU-28 (Guided Bomb Unit‐28) is a 4,000–5,000-pound (1,800–2,300 kg) class laser-guided "bunker busting" bomb produced originally by the Watervliet Arsenal, Watervliet, New York, built from modified M110 howitzers' barrels and dropped by F-111 aircraft.

In early October 2025, it was reported that Greece was considering selling at least 60 M110A2 guns along with 150,000 M110-compatible artillery shells of various types (M106 HEs, M650 HERAs, M404 ICMs, M509A1 DPICMs), which then would be transferred via the Czech Republic.^[8] It was passed through a Parliamentary Standing Committee on Armaments session, with the Council of General Staff Chiefs deeming them as Non-Essential Military Equipment, to be provided to Ukraine "as-is". The Government Council for National Security which has the final say, was expected to convene for a final decision.^[9][10]

In April 2026, Ukraine received an undisclosed number of systems which were put in service with the 52nd Separate Artillery Brigade of the Armed Forces of Ukraine.^[11]

• M14 dummy
• M106 HE
• M650 HE rocket assist projectile (RAP)
• M509 ICM
• M404 ICM anti-personnel (airburst)
• M426 agent GB Sarin
• M422A1 Artillery Fired Atomic Projectile^[12]
• M424 High Altitude Spotting Round for the M422 projectile
• XM753 Atomic RA (rocket assisted)^[13]

• List of U.S. military vehicles by model number
• 2S7 Pion – Soviet L/55.3 203 mm self-propelled cannon
• 2S4 Tyulpan – Soviet 240 mm self-propelled mortar
• List of crew-served weapons of the US Armed Forces
• M55 – 203 mm self-propelled gun, predecessor to the M110
• M107 – a 175 mm self-propelled gun on the same chassis
• Sholef – Israeli 155 mm self-propelled howitzer
• T92 Howitzer Motor Carriage – a 240 mm howitzer M1 fitted on a M26 Pershing chassis