M242 Bushmaster
Encyclopedia
The M242 Bushmaster is a 25 mm (25×137mm)
chain-fed
autocannon
. It is used extensively by the US armed forces
, as well as by NATO's and some other nations' forces in ground combat vehicle
s and watercraft. Originally, the weapon was designed and manufactured by McDonnell Douglas
(later acquired by the Boeing Corporation
); however it is now produced by Alliant Techsystems
(ATK) of Mesa, Arizona
.
It is an externally powered, chain driven, single-barrel weapon which may be fired in semi-automatic or automatic modes. It is fed by a metallic link belt and has dual-feed capability. The term "chain gun" derives from the use of a roller chain that drives the bolt back and forth. The gun can destroy lightly armored vehicles and aerial targets (such as helicopters and slow-flying aircraft). It can also suppress enemy positions such as exposed troops, dug-in positions, and occupied built-up areas. The standard rate of fire is 180 rounds
per minute. The weapon has an effective range of 3000 metres (9,842.5 ft), depending on the type of ammunition used.
The Bushmaster project started as an offshoot of the US Army
's MICV-65
program that was attempting to introduce a new infantry fighting vehicle
to replace their existing M113
s. Part of this program called for a new scout vehicle to replace the M114, a parallel development taking place under the XM800 Armored Reconnaissance Scout Vehicle
. Both the XM800 and the cavalry version of the XM701 MICV vehicles were armed with the M139, a US-built version of the Hispano-Suiza HS.820
20 mm autocannon
.
During the testing phase the Army eventually rejected the XM701 and started work on a newer design known as the XM723. Soon after the XM800 was also rejected. This led to the combination of the two programs, moving the scout role to the cavalry version of the XM723.
At the same time, the M139 proved to be disappointing and a contract for a new weapon to replace it started in 1972 at Hughes Aircraft
as the Vehicle Rapid-Fire Weapons System-Successor, or VRFWS-S. This was essentially a power-driven gun firing similar ammunition as the HS.820, the power driven mechanism would ensure operation even in the case of a misfire.
Progress on the VRFWS-S was slow, and eventually resulted in a switch to a much more powerful 25 mm round. Similar delays in the MICV program meant the ultimate vehicles descending from their efforts, the M2/M3 Bradley Fighting Vehicle, did not enter production until 1981, by which point the Bushmaster had matured. Since 1990, there have been several enhancements made upon the weapon, resulting in the Enhanced 25 mm gun.
To date, more than 10,500 weapons are in service. One of the major reasons for this popularity is the extremely reliable nature of the weapon. It has a rating of 22,000 mean rounds between failure (MRBF), much higher than many comparable devices.
s, the M242 does not depend on gas or recoil
to actuate its firing system. Instead, it uses a 1 hp DC
motor
, positioned in the receiver
to drive the chain and dual-feed system. This system uses sprockets and extractor grooves to feed, load, fire, extract, and eject rounds. A system of clutches provides for an alternate sprocket to engage and thus allows the gunner to switch between armor piercing
and high explosive rounds.
The weapon assembly consists of three parts: the barrel assembly, the feeder assembly, and the receiver assembly. The three-part structure makes it possible for a single person to install or remove the system despite its considerable total weight.
The M242 weapon system has both electrical and manual fire control and can be operated electrically or manually. In doing so, the gunner can choose from three rates of fire: (1) Single Shot Semi-Automatic, in which the gunner can shoot as fast as the trigger can be operated; (2) Low Rate Fully Automatic, in which the weapon fires 100 rounds a minute, plus or minus 25 rounds; and (3) High Rate Fully Automatic, in which the weapon fires 200 rounds a minute, plus or minus 25 rounds.
it is likely to encounter, up to and including some tank
s. The ammunition used in the M242 may also be used in a variety of weapons such as the GAU-12 Equalizer
, the French
Giat M811
, or the Swiss
Oerlikon KBA weapon system. It has the capability to fire U.S. manufactured ammunition as well as the NATO equivalents thereof. Primarily though, it fires six types of rounds: the M791, M792, M793, M910, MK210, and M919.
The M242 is currently in use by the United States
Army
, Navy
, Marine Corps
, and Coast Guard
, the New Zealand Army
, Royal New Zealand Navy
, the Norwegian Army
, the Spanish Army
, the Swiss Army
, the Canadian Army
, the Australian Army
and Navy
, the Israeli Navy, Philippine Navy
, the Singapore Army
and Republic of Singapore Navy
as well as several others. The wide usage results in several variations and modifications on the standard M242 weapon system.
(a successor to the M242) was used on the Marine Corps' Expeditionary Fighting Vehicle
(EFV).
The M242 is also a popular choice of primary armament for armoured fighting vehicle
s manufactured around the world, such as Singapore
's Bionix AFV
s and as the Rafael OWS-25
mounted on upgraded M113A2 Ultra IFVs.
barrel, an enhanced feeder, and an enhanced receiver. The weapon systems also received minor upgrades such as quick-detachable link covers, a larger breech assembly, a high efficiency muzzle brake
, longer recoil
, an integral round counter, an extended life firing pin and spring, and a triple-spring drive clutch. It was first put to use on the M2A3 Bradley, the third version of the M2 Bradley Fighting Vehicle.
weapon, the 5-barreled GAU-12/U
. The sister weapon of the M242, the 30 mm caliber
M230 Chain Gun
, is standard equipment on the Boeing AH-64 Apache attack helicopter
.
/Hispano-Suiza
20mm Mk 16 series of guns. In 1986, this requirement was satisfied with the introduction of the Mk 38 Mod 0 weapons system. A derivative of the M242 system, the Mk 38 consists of the M242 chain gun and the Mk 88 Mod 0 machine gun mount. It provides ships with defensive and offensive gunfire capability for the engagement of a variety of surface targets. Designed primarily as a close-range defensive measure, it provides protection against patrol boat
s, floating mines
, and various shore-based targets. The US Navy also developed a high ROF
variant under the designation Mk 46 Mod 0.
designated Mk 38 Mod 2, which is remotely operated and includes an Electronic Optical Sight, Laser Range-Finder, FLIR, and a more reliable feeding system, enhancing the weapon systems capabilities and accuracy. In 2006 the Sri Lanka Navy added M242 to its fleet of Fast Attack Craft
.
The system is also in used by the Republic of Singapore Navy
's Endurance class landing platform dock ship
s and were deployed as part of coalition forces' port security efforts in Iraq
as well as anti-piracy roles in the Gulf of Aden
. Aside from that, the Police Coast Guard
's New Coastal Patrol Craft (NCPC) has adopted the system as its main armament.
25 mm caliber
The 25x137 mm caliber/.98425 inch is one of the standard sizes of cannon and autocannon ammunition for NATO forces. The round itself has a length of approximately 223 mm .-Usage:...
chain-fed
Chain gun
A chain gun is a type of machine gun or autocannon that uses an external source of power, rather than diverting energy from the cartridge, to cycle the weapon, and does so via a continuous loop of chain similar to that used on a motorcycle or bicycle. "Chain gun" is a registered trademark of...
autocannon
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...
. It is used extensively by the US armed forces
United States armed forces
The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...
, as well as by NATO's and some other nations' forces in ground combat vehicle
Combat vehicle
A combat vehicle, also known as a ground combat vehicle, is a self-propelled, weaponized military vehicle used for combat operations. Combat vehicles can be wheeled or tracked.- Automation :...
s and watercraft. Originally, the weapon was designed and manufactured by McDonnell Douglas
McDonnell Douglas
McDonnell Douglas was a major American aerospace manufacturer and defense contractor, producing a number of famous commercial and military aircraft. It formed from a merger of McDonnell Aircraft and Douglas Aircraft in 1967. McDonnell Douglas was based at Lambert-St. Louis International Airport...
(later acquired by the Boeing Corporation
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
); however it is now produced by Alliant Techsystems
Alliant Techsystems
Alliant Techsystems Inc., most commonly known by its ticker symbol, ', is one of the largest aerospace and defense companies in the United States with more than 18,000 employees in 22 states, Puerto Rico and internationally, and 2010 revenues in excess of an estimated...
(ATK) of Mesa, Arizona
Mesa, Arizona
According to the 2010 Census, the racial composition of Mesa was as follows:* White: 77.1% * Hispanic or Latino : 26.54%* Black or African American: 3.5%* Two or more races: 3.4%* Native American: 2.4%...
.
It is an externally powered, chain driven, single-barrel weapon which may be fired in semi-automatic or automatic modes. It is fed by a metallic link belt and has dual-feed capability. The term "chain gun" derives from the use of a roller chain that drives the bolt back and forth. The gun can destroy lightly armored vehicles and aerial targets (such as helicopters and slow-flying aircraft). It can also suppress enemy positions such as exposed troops, dug-in positions, and occupied built-up areas. The standard rate of fire is 180 rounds
Cartridge (firearms)
A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...
per minute. The weapon has an effective range of 3000 metres (9,842.5 ft), depending on the type of ammunition used.
History
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
's MICV-65
MICV-65
MICV-65, short for Mechanized Infantry Combat Vehicle, 1965, was a US Army project that studied a number of armored fighting vehicles that would replace the M113 and M114 as well as take on a variety of new roles. A number of designs were studied as part of the MICV project, but none of the entered...
program that was attempting to introduce a new infantry fighting vehicle
Infantry fighting vehicle
An infantry fighting vehicle , also known as a mechanized infantry combat vehicle , is a type of armoured fighting vehicle used to carry infantry into battle and provide fire support for them...
to replace their existing M113
M113 armored personnel carrier
The M113 is a fully tracked armored personnel carrier that has formed the backbone of the United States Army's mechanized infantry units from the time of its first fielding in Vietnam in April 1962. The M113 was the most widely used armored vehicle of the U.S...
s. Part of this program called for a new scout vehicle to replace the M114, a parallel development taking place under the XM800 Armored Reconnaissance Scout Vehicle
XM800 Armored Reconnaissance Scout Vehicle
The XM800 Armored Reconnaissance Scout Vehicle, or ARSV, was an experimental scout vehicle developed by the US Army in the 1970s. It was part of a series of armored vehicles being designed by the Army to replace their existing armored personnel carriers, the M113 and M114, with vehicles with...
. Both the XM800 and the cavalry version of the XM701 MICV vehicles were armed with the M139, a US-built version of the Hispano-Suiza HS.820
Hispano-Suiza HS.820
The Hispano-Suiza HS.820 was a 20 mm autocannon developed primarily for aircraft use, but more widely used in a series of ground-based anti-aircraft guns...
20 mm autocannon
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...
.
During the testing phase the Army eventually rejected the XM701 and started work on a newer design known as the XM723. Soon after the XM800 was also rejected. This led to the combination of the two programs, moving the scout role to the cavalry version of the XM723.
At the same time, the M139 proved to be disappointing and a contract for a new weapon to replace it started in 1972 at Hughes Aircraft
Hughes Aircraft
Hughes Aircraft Company was a major American aerospace and defense contractor founded in 1932 by Howard Hughes in Culver City, California as a division of Hughes Tool Company...
as the Vehicle Rapid-Fire Weapons System-Successor, or VRFWS-S. This was essentially a power-driven gun firing similar ammunition as the HS.820, the power driven mechanism would ensure operation even in the case of a misfire.
Progress on the VRFWS-S was slow, and eventually resulted in a switch to a much more powerful 25 mm round. Similar delays in the MICV program meant the ultimate vehicles descending from their efforts, the M2/M3 Bradley Fighting Vehicle, did not enter production until 1981, by which point the Bushmaster had matured. Since 1990, there have been several enhancements made upon the weapon, resulting in the Enhanced 25 mm gun.
To date, more than 10,500 weapons are in service. One of the major reasons for this popularity is the extremely reliable nature of the weapon. It has a rating of 22,000 mean rounds between failure (MRBF), much higher than many comparable devices.
Description
Unlike most automatic firearmFirearm
A firearm is a weapon that launches one, or many, projectile at high velocity through confined burning of a propellant. This subsonic burning process is technically known as deflagration, as opposed to supersonic combustion known as a detonation. In older firearms, the propellant was typically...
s, the M242 does not depend on gas or recoil
Recoil
Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
to actuate its firing system. Instead, it uses a 1 hp DC
Direct current
Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...
motor
Electric motor
An electric motor converts electrical energy into mechanical energy.Most electric motors operate through the interaction of magnetic fields and current-carrying conductors to generate force...
, positioned in the receiver
Receiver (firearms)
In firearms terminology, the receiver is the part of a firearm that houses the operating parts. The receiver usually contains the bolt carrier group, trigger group, and magazine port. In most handguns, the receiver, or frame, holds the magazine well or rotary magazine as well as the trigger mechanism...
to drive the chain and dual-feed system. This system uses sprockets and extractor grooves to feed, load, fire, extract, and eject rounds. A system of clutches provides for an alternate sprocket to engage and thus allows the gunner to switch between armor piercing
Armor-piercing shot and shell
An armor-piercing shell is a type of ammunition designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions...
and high explosive rounds.
The weapon assembly consists of three parts: the barrel assembly, the feeder assembly, and the receiver assembly. The three-part structure makes it possible for a single person to install or remove the system despite its considerable total weight.
The M242 weapon system has both electrical and manual fire control and can be operated electrically or manually. In doing so, the gunner can choose from three rates of fire: (1) Single Shot Semi-Automatic, in which the gunner can shoot as fast as the trigger can be operated; (2) Low Rate Fully Automatic, in which the weapon fires 100 rounds a minute, plus or minus 25 rounds; and (3) High Rate Fully Automatic, in which the weapon fires 200 rounds a minute, plus or minus 25 rounds.
Ammunition
A wide range of ammunition has been developed for this weapon, providing it with the capability to defeat the majority of armored vehiclesArmoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
it is likely to encounter, up to and including some tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...
s. The ammunition used in the M242 may also be used in a variety of weapons such as the GAU-12 Equalizer
GAU-12 Equalizer
The General Dynamics GAU-12/U Equalizer is a five-barrel 25 mm Gatling gun-style rotary cannon. The GAU-12/U is used by the United States, Italy and Spain, which mount the weapon in their fighter jets such as the AV-8B Harrier II, airborne gunships such as the Lockheed AC-130, and land-based...
, the French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
Giat M811
Giat M811
The M811 is an automatic, externally-powered, single or dual fed cannon firing NATO standard 25 mm ammunition , designed by Nexter Systems .-History:...
, or the Swiss
Switzerland
Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....
Oerlikon KBA weapon system. It has the capability to fire U.S. manufactured ammunition as well as the NATO equivalents thereof. Primarily though, it fires six types of rounds: the M791, M792, M793, M910, MK210, and M919.
- M791 Armor Piercing Discarding SabotSabotA sabot is a device used in a firearm or cannon to fire a projectile, such as a bullet, that is smaller than the bore diameter, or which must be held in a precise position. The term is also applied to a battery stub case, a device used similarly to make a small electrical battery usable in a...
with Tracer- 5.7 million rounds produced
- The APDS-T penetrates lightly armored vehiclesArmoured fighting vehicleAn armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
, self-propelled artillerySelf-propelled artillerySelf-propelled artillery vehicles are combat vehicles armed with artillery. Within the term are covered self-propelled guns and rocket artillery...
, and aerial targets such as helicopterHelicopterA helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...
s and various slow-moving, fixed-wing aircraftAircraftAn aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
.
- M792 High Explosive Incendiary with Tracer and Self Destruct
- 5.5 million rounds produced
- The HEI-T can destroy unarmored vehicles and helicopters and suppress antitank missile positions and enemy squads out to a maximum effective range of 3,000 meters.
- M793 Target Practice with TracerTracer ammunitionTracer ammunition are bullets that are built with a small pyrotechnic charge in their base. Ignited by the burning powder, the phosphorus tail burns very brightly, making the projectile visible to the naked eye...
- 11.5 million rounds produced
- The TP-T cartridge is a fixed-type, percussion-primed training round that matches the High Explosive Incendiary with Tracer (HEI-T MK210) round ballistically. The TP-T's tracer is visible out to 2,000 meters, however, the round has a maximum effective range (accuracy-limited) of 1,600 meters.
- M910 Target Practice Discarding Sabot with Tracer
- The TPDS-T replicates the flight pattern of the M791 Armor Piercing Discarding SabotSabotA sabot is a device used in a firearm or cannon to fire a projectile, such as a bullet, that is smaller than the bore diameter, or which must be held in a precise position. The term is also applied to a battery stub case, a device used similarly to make a small electrical battery usable in a...
with Tracer (APDS-T) round. The TPDS-T allows units to realistically practice sabot engagements.
- The TPDS-T replicates the flight pattern of the M791 Armor Piercing Discarding Sabot
- MK210 High Explosive Incendiary with Tracer
- 228,000 rounds produced
- Used by the U. S. Navy in their Mk38 naval weapon system.
- M919 Armor-Piercing, Fin-Stabilized Discarding Sabot With Tracer.
- The APFSDS-T round penetrates light armored vehicles, self-propelled artillery, and aerial targets, which includes helicopters and slow-moving fixed-wing aircraft. It is identical to the M791 Armor Piercing Discarding Sabot with Tracer except in its quality of being fin-stabilized, and that the dart is made of depleted uraniumDepleted uraniumDepleted uranium is uranium with a lower content of the fissile isotope U-235 than natural uranium . Uses of DU take advantage of its very high density of 19.1 g/cm3...
.
- The APFSDS-T round penetrates light armored vehicles, self-propelled artillery, and aerial targets, which includes helicopters and slow-moving fixed-wing aircraft. It is identical to the M791 Armor Piercing Discarding Sabot with Tracer except in its quality of being fin-stabilized, and that the dart is made of depleted uranium
Variations
The M242 is currently in use by the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
, Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
, Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...
, and Coast Guard
United States Coast Guard
The United States Coast Guard is a branch of the United States Armed Forces and one of the seven U.S. uniformed services. The Coast Guard is a maritime, military, multi-mission service unique among the military branches for having a maritime law enforcement mission and a federal regulatory agency...
, the New Zealand Army
New Zealand Army
The New Zealand Army , is the land component of the New Zealand Defence Force and comprises around 4,500 Regular Force personnel, 2,000 Territorial Force personnel and 500 civilians. Formerly the New Zealand Military Forces, the current name was adopted around 1946...
, Royal New Zealand Navy
Royal New Zealand Navy
The Royal New Zealand Navy is the maritime arm of the New Zealand Defence Force...
, the Norwegian Army
Norwegian Army
Norway achieved full independence in 1905, and in the first century of its short life has contributed to two major conflicts, the Cold War and the War on Terror. The Norwegian Army currently operates in the north of Norway and in Afghanistan as well as in Eastern Europe. The Army is the oldest of...
, the Spanish Army
Spanish Army
The Spanish Army is the terrestrial army of the Spanish Armed Forces responsible for land-based military operations. It is one of the oldest active armies - dating back to the 15th century.-Introduction:...
, the Swiss Army
Military of Switzerland
The Swiss Armed Forces perform the roles of Switzerland's militia and regular army. Under the country's militia system, professional soldiers constitute about 5 percent of military personnel; the rest are male citizen conscripts 19 to 34 years old...
, the Canadian Army
Canadian Forces
The Canadian Forces , officially the Canadian Armed Forces , are the unified armed forces of Canada, as constituted by the National Defence Act, which states: "The Canadian Forces are the armed forces of Her Majesty raised by Canada and consist of one Service called the Canadian Armed Forces."...
, the Australian Army
Australian Army
The Australian Army is Australia's military land force. It is part of the Australian Defence Force along with the Royal Australian Navy and the Royal Australian Air Force. While the Chief of Defence commands the Australian Defence Force , the Army is commanded by the Chief of Army...
and Navy
Royal Australian Navy
The Royal Australian Navy is the naval branch of the Australian Defence Force. Following the Federation of Australia in 1901, the ships and resources of the separate colonial navies were integrated into a national force: the Commonwealth Naval Forces...
, the Israeli Navy, Philippine Navy
Philippine Navy
The Philippine Navy is the naval arm of the Armed Forces of the Philippines . Its official name in Filipino is Hukbong Dagat ng Pilipinas, literally, "Sea Force of the Philippines"....
, the Singapore Army
Singapore Army
The Singapore Army is the branch of the Singapore Armed Forces responsible for land operations. It is the largest of the three armed services and heavily reliant on a conscript army, comprising the majority of Singapore's Operationally Ready National Servicemen .-Capabilities:The mission of the...
and Republic of Singapore Navy
Republic of Singapore Navy
The Republic of Singapore Navy is the naval component of the Singapore Armed Forces , responsible for the defence of Singapore against sea-borne threats and protection of its sea lines of communications. Operating within the crowded littoral waters of the Singapore Strait, the RSN is regarded as...
as well as several others. The wide usage results in several variations and modifications on the standard M242 weapon system.
Ground Vehicles
The M242 is standard equipment on the U. S. Army M2 and M3 Bradley fighting vehicles, it is also in use on the LAV-25. Before the project was cancelled, the Bushmaster II 30 mm chain gunBushmaster II
The Mk44 Bushmaster II is a 30 mm chain gun manufactured by Alliant Techsystems. It is a derivative of the 25 mm M242 Bushmaster, and uses some 70% of the same parts as the M242 while increasing the firepower by as much as 50% with the 20% increase in caliber size. The barrel is chromium-plated...
(a successor to the M242) was used on the Marine Corps' Expeditionary Fighting Vehicle
Expeditionary Fighting Vehicle
The Expeditionary Fighting Vehicle is an amphibious assault vehicle that was being developed for the U.S. Marine Corps. It is launched at sea, from an amphibious assault ship beyond the horizon, able to transport a full Marine rifle squad to shore...
(EFV).
The M242 is also a popular choice of primary armament for armoured fighting vehicle
Armoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
s manufactured around the world, such as Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
's Bionix AFV
Bionix AFV
The Bionix is a family of tracked Singaporean armoured fighting vehicles developed by Singapore Technologies Kinetics . Intended to augment the Singapore Army's aging M113 armoured personnel carriers, it is the first indigenous armoured vehicle to be developed in Southeast Asia...
s and as the Rafael OWS-25
Rafael Overhead Weapon Station
The Rafael Overhead Weapon Station is a remote weapon station developed by Rafael Advanced Defense Systems in cooperation with the Israel Defense Forces. It has been superseded by the Rafael Samson Remote Controlled Weapon Station...
mounted on upgraded M113A2 Ultra IFVs.
Enhanced 25 mm gun
Work on an upgraded weapon began in 1990. In doing so, three major systems and seven minor systems were improved. The modifications began with introducing a chrome-linedChrome plating
Chrome plating, often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object. The chromed layer can be decorative, provide corrosion resistance, ease cleaning procedures, or increase surface hardness.-Process:A component to be chrome plated will...
barrel, an enhanced feeder, and an enhanced receiver. The weapon systems also received minor upgrades such as quick-detachable link covers, a larger breech assembly, a high efficiency muzzle brake
Muzzle brake
Muzzle brakes and recoil compensators are devices that are fitted to the muzzle of a firearm or cannon to redirect propellant gases with the effect of countering both recoil of the gun and unwanted rising of the barrel during rapid fire...
, longer recoil
Recoil
Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
, an integral round counter, an extended life firing pin and spring, and a triple-spring drive clutch. It was first put to use on the M2A3 Bradley, the third version of the M2 Bradley Fighting Vehicle.
Aircraft
The M242 is not used on aircraft. The AC-130U and the AV-8 Harrier II uses a different 25 mm caliber25 mm caliber
The 25x137 mm caliber/.98425 inch is one of the standard sizes of cannon and autocannon ammunition for NATO forces. The round itself has a length of approximately 223 mm .-Usage:...
weapon, the 5-barreled GAU-12/U
GAU-12 Equalizer
The General Dynamics GAU-12/U Equalizer is a five-barrel 25 mm Gatling gun-style rotary cannon. The GAU-12/U is used by the United States, Italy and Spain, which mount the weapon in their fighter jets such as the AV-8B Harrier II, airborne gunships such as the Lockheed AC-130, and land-based...
. The sister weapon of the M242, the 30 mm caliber
30 mm caliber
30 mm caliber ammunition is usually used in autocannon. Such ammunition includes NATO standard 30 × 173 mm and 30 × 113 mm and Soviet 30 × 165 mm ammunition widely used around the world....
M230 Chain Gun
M230 Chain Gun
The Hughes M230 Chain Gun is a 30 mm, single-barrel automatic cannon developed by Hughes and now manufactured by Alliant Techsystems. It is an electrically operated chain gun, a weapon that uses external power instead of recoil to load its rounds....
, is standard equipment on the Boeing AH-64 Apache attack helicopter
Attack helicopter
An attack helicopter is a military helicopter with the primary role of an attack aircraft, with the capability of engaging targets on the ground, such as enemy infantry and armored vehicles...
.
Naval
In 1977, the U. S. Navy realized that it needed a replacement for the OerlikonOerlikon 20 mm cannon
The Oerlikon 20 mm cannon is a series of autocannons, based on an original design by Reinhold Becker of Germany, very early in World War I, and widely produced by Oerlikon Contraves and others...
/Hispano-Suiza
Hispano-Suiza HS.404
The Hispano-Suiza HS.404 was an autocannon widely used as both an aircraft and land weapon in the 20th century by British, American, French, and numerous other military services. The cannon is also referred to as Birkigt type 404, after its designer. Firing a 20 mm caliber projectile, it delivered...
20mm Mk 16 series of guns. In 1986, this requirement was satisfied with the introduction of the Mk 38 Mod 0 weapons system. A derivative of the M242 system, the Mk 38 consists of the M242 chain gun and the Mk 88 Mod 0 machine gun mount. It provides ships with defensive and offensive gunfire capability for the engagement of a variety of surface targets. Designed primarily as a close-range defensive measure, it provides protection against patrol boat
Patrol boat
A patrol boat is a relatively small naval vessel generally designed for coastal defense duties.There have been many designs for patrol boats. They may be operated by a nation's navy, coast guard, or police force, and may be intended for marine and/or estuarine or river environments...
s, floating mines
Naval mine
A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...
, and various shore-based targets. The US Navy also developed a high ROF
Rate of fire
Rate of fire is the frequency at which a specific weapon can fire or launch its projectiles. It is usually measured in rounds per minute , or per second .-Overview:...
variant under the designation Mk 46 Mod 0.
Mk 38 Mod 2
Recently, several US Navy platforms have been outfitted with a newer version, the Typhoon Weapon SystemTyphoon Weapon System
The Typhoon is a type of remote weapon station manufactured by Rafael Advanced Defense Systems of Israel, and it shares similar design principles and common technologies with Samson Remote Controlled Weapon Station , a land-based system manufactured by the same developer...
designated Mk 38 Mod 2, which is remotely operated and includes an Electronic Optical Sight, Laser Range-Finder, FLIR, and a more reliable feeding system, enhancing the weapon systems capabilities and accuracy. In 2006 the Sri Lanka Navy added M242 to its fleet of Fast Attack Craft
Ultra Fast Attack Craft
The Ultra Fast Attack Craft, commonly known as the Colombo Class, is an ultra high-speed class of patrol boats meant for a variety of naval missions from typical off-shore coastal patrol mission profiles to high-speed, high-maneuver littoral warfare...
.
The system is also in used by the Republic of Singapore Navy
Republic of Singapore Navy
The Republic of Singapore Navy is the naval component of the Singapore Armed Forces , responsible for the defence of Singapore against sea-borne threats and protection of its sea lines of communications. Operating within the crowded littoral waters of the Singapore Strait, the RSN is regarded as...
's Endurance class landing platform dock ship
Endurance class landing platform dock ship
The Endurance class landing platform dock ships are the largest class of ships in the Republic of Singapore Navy . They were designed and built locally by Singapore Technologies Marine to replace the old County class tank landing ships...
s and were deployed as part of coalition forces' port security efforts in Iraq
Iraq
Iraq ; officially the Republic of Iraq is a country in Western Asia spanning most of the northwestern end of the Zagros mountain range, the eastern part of the Syrian Desert and the northern part of the Arabian Desert....
as well as anti-piracy roles in the Gulf of Aden
Gulf of Aden
The Gulf of Aden is located in the Arabian Sea between Yemen, on the south coast of the Arabian Peninsula, and Somalia in the Horn of Africa. In the northwest, it connects with the Red Sea through the Bab-el-Mandeb strait, which is about 20 miles wide....
. Aside from that, the Police Coast Guard
Police Coast Guard
The Police Coast Guard is the Marine Police division of the Singapore Police Force which also takes on roles of the coast guard typically handled by the military or as separate organisations in other countries...
's New Coastal Patrol Craft (NCPC) has adopted the system as its main armament.
Operators
-
- Army: ASLAV-25ASLAVThe Australian Service Light Armoured Vehicle , is an Australian version of the Light Armoured Vehicle designed and manufactured by General Dynamics Land Systems Canada for the U.S. Marines. The initial design was the MOWAG Piranha 8x8, however the vehicle was re-designed to meet North American...
- Navy: Armidale class patrol boatArmidale class patrol boatThe Armidale class is a class of patrol boats built for the Royal Australian Navy . Planning for a class of twelve vessels to replace the fifteen Fremantle class patrol boats began in 1993 as a joint project with the Royal Malaysian Navy, but was cancelled when Malaysia pulled out of the process...
s - Land: LAV IIILAV IIIThe LAV III armoured vehicle is the latest in the Generation III Light Armoured Vehicle series built by General Dynamics Land Systems, entering service in 1999. It is based on the Swiss MOWAG Piranha IIIH 8x8....
- Navy: Super Dvora Mk III class patrol boat, Shaldag class fast patrol boatShaldag class fast patrol boatThe Shaldag class Fast Patrol Boat is a small but fast class of patrol boats developed for the Israeli Sea Corps and launched in 1989, it has since seen service with several other navies. Designed for security tasks where high intercept speeds are required, such as interdiction of terrorism and...
- Army: ACV-300 IFV
- Army: NZLAVNZLAVThe NZLAV armoured fighting vehicle is a variant of the General Dynamics LAV III which itself is a variant of the MOWAG Piranha IIIH 8x8. The New Zealand army purchased 105 vehicles in 2003. It was developed by Canada and is the primary armoured vehicle of the New Zealand military...
- Navy: HMNZS Canterbury multi-role vessel and Protector class offshore patrol vessels
- Army: Bionix 25, M113A2 Ultra IFV
- Navy: Endurance class landing platform dock shipEndurance class landing platform dock shipThe Endurance class landing platform dock ships are the largest class of ships in the Republic of Singapore Navy . They were designed and built locally by Singapore Technologies Marine to replace the old County class tank landing ships...
- Army: VEC-M1VEC-M1The Pegaso VEC-M1 is a Spanish military cavalry reconnaissance vehicle. It started service in the Spanish Army in 1980 as BMR-625 VEC and all of them were upgraded in late 90's to the M1 version....
- Army: M2/M3 Bradley
- Marine Corps: LAV-25
- Army: ASLAV-25
See also
- List of artillery
- M230 30 mm chain gunM230 Chain GunThe Hughes M230 Chain Gun is a 30 mm, single-barrel automatic cannon developed by Hughes and now manufactured by Alliant Techsystems. It is an electrically operated chain gun, a weapon that uses external power instead of recoil to load its rounds....
- Bushmaster II 30 mm chain gun
- Bushmaster III 35mm/50 chain gunBushmaster IIIThe Bushmaster III is an automatic/semi-automatic cannon designed and built by Alliant Techsystems. It is based on the M242 Bushmaster originally developed by Alliant Techsystems...
- List of weapons of the United States Marine Corps
- List of crew-served weapons of the U.S. armed forces
External links
- Alliant Techsystems (ATK): M242 Bushmaster - manufacturer's brochure
- Federation of American Scientists: M242
- NavWeaps.Com: 25 mm/87 (1") Mark 38 Machine Gun System
- U. S. Army Field Manual 3-22.1
- Canadian-American Strategic Review: M242