M20 recoilless rifle
Encyclopedia
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
75 mm caliber recoilless rifle
Recoilless rifle
A recoilless rifle or recoilless gun is a lightweight weapon that fires a heavier projectile than would be practical to fire from a recoiling weapon of comparable size. Technically, only devices that use a rifled barrel are recoilless rifles. Smoothbore variants are recoilless guns...
used during the last months of the Second World War and extensively during the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
. It could be fired from an M1917A1 .30 caliber machine gun tripod, or from a vehicle mount, typically a Jeep
Jeep
Jeep is an automobile marque of Chrysler . The first Willys Jeeps were produced in 1941 with the first civilian models in 1945, making it the oldest off-road vehicle and sport utility vehicle brand. It inspired a number of other light utility vehicles, such as the Land Rover which is the second...
. Its shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
warhead, also known as the HEAT
Heat
In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...
, was capable of penetrating 100 mm of armor. Although the weapon proved ineffective against the T-34 tank during the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
, 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
Bunker
A military bunker is a hardened shelter, often buried partly or fully underground, designed to protect the inhabitants from falling bombs or other attacks...
and other types of field fortifications.
History
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
the U.S. military recognized that a powerful lightweight weapon was needed for defending infantry and light armor units due to advancements in armor technology by enemy forces. The Ordnance Department Small Arms Division commenced development of the 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 on 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.
Recoilless rifles, such as the M20, were used successfully in large numbers by US forces during the Korean War
Korean War
The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...
, and by both sides in the First Vietnam War (1948–54), but were phased out after being replaced by wired guided missiles introduced during the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
in the 1960s and 1970s. Currently, M20 recoilless rifles are being used as part of the avalanche
Avalanche
An avalanche is a sudden rapid flow of snow down a slope, occurring when either natural triggers or human activity causes a critical escalating transition from the slow equilibrium evolution of the snow pack. Typically occurring in mountainous terrain, an avalanche can mix air and water with the...
control system used by the U.S. National Park Service
National Park Service
The National Park Service is the U.S. federal agency that manages all national parks, many national monuments, and other conservation and historical properties with various title designations...
. There are also pictures suggesting its use by guerrillas in the Lebanese Civil War
Lebanese Civil War
The Lebanese Civil War was a multifaceted civil war in Lebanon. The war lasted from 1975 to 1990 and resulted in an estimated 150,000 to 230,000 civilian fatalities. Another one million people were wounded, and today approximately 350,000 people remain displaced. There was also a mass exodus of...
.
Specifications
- Length: 6 ft 10 in (2.08 m)
- Weight: 114.5 lb (52 kg)
- Rifling: uniform right hand twist, 1 turn in 25
- Range: (HEAT) 7,000 yards (6.4 km)
- Muzzle velocity: (HEAT) 1,000 ft/s (300 m/s)
- Cartridge: 75 × 408 mm. R
- Caliber: 75 mm. (2.95 inches)
- Round weight:
- HE: 21.86 lb (9.92 kg)
- HEAT: 20.54 lb (9.32 kg)
- Smoke (T40, WP): 22.61 lb (10.26 kg)
- Armor penetration: 4 inches (100 mm)
See also
- M18 recoilless rifleM18 recoilless rifleThe M18 recoilless rifle was a 57 mm shoulder fired anti-tank recoilless rifle used by the U.S. Army in World War II and the Korean War. Recoilless rifles are capable of firing artillery-type shells at reduced velocities comparable to those of standard cannon, but with greater accuracy than...
– smaller caliber model of the same era - M29 WeaselM29 WeaselThe M29 Weasel was a World War II tracked vehicle, built by Studebaker, designed for operation in snow.-Design and development:The idea for the Weasel came from the work of British inventor Geoffrey Pyke in support of his proposals to attack Axis forces and industrial installations in Norway...
– the "M29C Type A" variant had a center mounted M20 as its armament