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M20 recoilless rifle

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M20 recoilless rifle
An M20 recoilless rifle in action during the Korean War
TypeRecoilless anti-tank weapon
Place of originUnited States
Service history
Used byUnited States
Production history
VariantsType 56
Mass103 lb (47 kg)
Length82 in (2.1 m)
Barrel length65 in (1.7 m)
Crew1 or 2[2]

Shell75 x 408 mm R[3] HE, HEAT, Smoke
Shell weight20.5–22.6 lb (9.3–10.3 kg)
Caliber75 mm (3.0 in)
CarriageM1917A1 tripod
Elevation−27° to +65°
Muzzle velocity1,000 ft/s (300 m/s)
Maximum firing range3.9 mi (6.3 km)[2]
An M20 recoilless rifle on display in the Royal Armouries at Fort Nelson
Sergeant Reckless, a decorated war horse serving with a US Marine Corps recoilless rifle platoon in the Korean War, stands beside a 75mm recoilless rifle

The M20 recoilless rifle is a U.S. 75 mm caliber recoilless rifle T21E12 that was used during the last months of the Second World War and extensively during the Korean War. It could be fired from an M1917A1 .30 caliber machine gun tripod, or from a vehicle mount, typically a Jeep. Its shaped charge warhead, also known as HEAT, was capable of penetrating 100 mm of armor. Although the weapon proved ineffective against the T-34 tank and most other tanks during the Korean War, it was used primarily as a close infantry support weapon to engage all types of targets including infantry and lightly armored vehicles. The M20 proved useful against pillboxes and other types of field fortifications.


During World War II, the U.S. military recognized that, due to advancements in armor technology by enemy forces, a powerful lightweight weapon was needed to defend infantry and light armor units. The Ordnance Department Small Arms Division commenced development of a recoilless rifle and, by 1944, models of a 75 mm recoilless rifle were being tested. Production of the M20 was underway by March 1945; only limited numbers were used by Allied troops in the European and Pacific theaters.

The M20 relied on a perforated artillery shell casing, combined with a rear vented breech using propellant gases from the firing of a shell, to greatly reduce the recoil of the weapon. It is this use of vented propellant gases that eliminated the need for a recoil system, thereby reducing the weight of the launcher and enhancing its use as a light infantry weapon.

The M20 was one of the main anti-tank weapons used by the U.S. military in the early days of the Korean War along with the 2.36-inch Bazooka. However, the recoilless rifle failed to destroy any North Korean T-34-85 during the Battle of Osan on July 5, 1950. After the deployment of the 3.5-inch M20 Super Bazooka in mid-July, the M20 recoilless rifle no longer functioned as an anti-tank weapon, and was used as an infantry support weapon. It was a very effective weapon to destroy enemy bunkers and trenches with easy transportation benefitted from light weight while providing great firepower.[4]

Recoilless rifles, such as the M20, were also used successfully in large numbers by both sides in the First Indochina War (1946–54). They were phased out after being replaced by wire guided missiles, which were introduced during the Vietnam War in the 1960s and 1970s. Until stockpiles of ammunition were exhausted in the 1990s, M20 recoilless rifles were used to start controlled avalanches by the U.S. National Forest Service and National Park Service.[5]

The Royal Moroccan Army used M20s during the Western Sahara War against the Polisario Front.[6]

China also produced unlicensed copies, known as the Type 52 and Type 56 (an upgraded version that could fire fin-stabilized HEAT shells). These versions were widely used by the North Vietnamese Army (NVA) and Vietcong guerrillas in the Vietnam War[7] and there are also pictures suggesting its use by guerrillas and militias in the Lebanese Civil War (1975–1990), such as the Amal Movement militia.[8]


See also[edit]


  1. ^ Huon, Jean (March 1992). "L'armement français en A.F.N." Gazette des Armes (in French). No. 220. pp. 12–16.
  2. ^ a b c Chamberlain, Peter (1975). Infantry, mountain, and airborne guns. Gander, Terry. New York: Arco. p. 58. ISBN 0668038195. OCLC 2067391.
  3. ^ "75-77 MM CALIBRE CARTRIDGES". www.quarryhs.co.uk. Retrieved 2017-10-02.
  4. ^ a b Bak, Dongchan (March 2021). Korean War : Weapons of the United Nations (PDF) (in Korean). Republic of Korea: Ministry of Defense Institute for Military History. pp. 71–75. ISBN 979-11-5598-079-8.
  5. ^ "United States Military Artillery for Avalanche Control Program:A Brief History in Time" (PDF). USDA Forest Service National Avalanche Center. Retrieved 2018-04-11.
  6. ^ Anthony Cordesman (2016). After The Storm: The Changing Military Balance in the Middle East. Bloomsbury Publishing. p. 112. ISBN 978-1-4742-9257-3.
  7. ^ Rottman, Gordon L. (10 Feb 2009). North Vietnamese Army Soldier 1958–75. Warrior 135. Osprey Publishing. p. 32. ISBN 9781846033711.
  8. ^ A Toyota Land Cruiser BJ40/42 of the AMAL militia in 1984 armed with a Chinese made Type 56 75mm recoilless rifle.
  9. ^ partisan1943 (April 2018). "Eastern Bloc militaries". Eastern Bloc militaries. Retrieved 2021-10-05.{{cite web}}: CS1 maint: numeric names: authors list (link)
  10. ^ a b c d e f g h i j k l m n o p q r s t u Gander, Terry J.; Cutshaw, Charles Q., eds. (2001). Jane's Infantry Weapons 2001/2002 (27th ed.). Coulsdon: Jane's Information Group. ISBN 9780710623171.
  11. ^ International Institute for Strategic Studies (2021). The Military Balance. Taylor & Francis. p. 455. ISBN 9781032012278.
  12. ^ "Ethiopians in the Korean War: WWII gear used". wwiiafterwwii.wordpress.com. August 18, 2016.[self-published source]
  13. ^ Jalesveva Jayamahe, p.125
  14. ^ Park, Il-Song; Yang, Yong-Jo; Son, Kyu-Suk. "The Korean War and the Forces of the Kingdom of Netherlands". A History of Netherland Forces' Participation in the Korean War (PDF). Translated by Lee, Jang-Song. Ministry of Patriots and Veterans Affairs (South Korea). pp. 67–68.
  15. ^ Gordon L. Rottman (2010). Army of the Republic of Vietnam 1955–75. Vol. Men-at-Arms 458. Osprey Publishing. p. 7. ISBN 9781849081818.
  16. ^ "Turkey Turkish army land ground armed defense forces military equipment armored vehicle intelligence | Turkey Turkish army land ground forces UK | West Europe army military land forces UK". 2018-08-08. Archived from the original on 2018-08-08. Retrieved 2021-05-03.


  • TM 9-2300 Artillery Materiel and Associated Equipment. dated May 1949
  • TM 9-314 operators, and maintenance
  • SNL C-74 parts

External links[edit]