CAR-15
Encyclopedia
The Colt Automatic Rifle-15 Military Weapons System or CAR-15 was a family of AR-15
AR-15
The AR-15 is a lightweight, 5.56 mm, air-cooled, gas-operated, magazine-fed semi-automatic rifle, with a rotating-lock bolt, actuated by direct impingement gas operation. It is manufactured with the extensive use of aluminum alloys and synthetic materials....

 and M16 rifle
M16 rifle
The M16 is the United States military designation for the AR-15 rifle adapted for both semi-automatic and full-automatic fire. Colt purchased the rights to the AR-15 from ArmaLite, and currently uses that designation only for semi-automatic versions of the rifle. The M16 fires the 5.56×45mm NATO...

–based firearms marketed by Colt
Colt's Manufacturing Company
Colt's Manufacturing Company is a United States firearms manufacturer, whose first predecessor corporation was founded in 1836 by Sam Colt. Colt is best known for the engineering, production, and marketing of firearms over the later half of the 19th and the 20th century...

 in the late 1960s and early 1970s. Due to their compact size, the short-barreled Colt Commando and XM177 versions of this family continued to be issued to the U.S. military after 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...

.

The CAR-15 name was an attempt to re-associate the AR-15 name with Colt, since the AR initially stood for ArmaLite
ArmaLite
ArmaLite is the name of a small arms engineering facility founded in the early 1950s, and once associated with the Fairchild Engine and Airplane Corporation. ArmaLite was formally incorporated as a subdivision of Fairchild on October 1, 1954...

 Rifle, the original manufacturer. Colt later abandoned the CAR-15 concept, but continued to make variations, using the M16 brand for military-oriented models and the Colt AR-15 brand for law enforcement and civilian models. However, in present usage, CAR-15 is used as a generic name for carbine
Carbine
A carbine , from French carabine, is a longarm similar to but shorter than a rifle or musket. Many carbines are shortened versions of full rifles, firing the same ammunition at a lower velocity due to a shorter barrel length....

-length M16 and AR-15 variants.

Specifically, "Colt Commando" currently refers to the ultrashort 11.5-inch barrel assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...

 of the Model 733 series. By comparison, the M4 Carbine
M4 Carbine
The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter variant of the M16A2 assault rifle, with 80% parts commonality.It is a gas-operated,...

 has an 14.5-inch barrel, while that of the M16 assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...

 is 20 inch (0.508 m).

History

Starting in 1965, Colt attempted to market the M16 rifle as a modular
Modular design
Modular design, or "modularity in design" is an approach that subdivides a system into smaller parts that can be independently created and then used in different systems to drive multiple functionalities...

 weapons platform that could fulfill all of the various needs of an army, similar to the marketing plans for the AR-10
AR-10
The AR-10 is an American 7.62 mm battle rifle developed by Eugene Stoner in the late 1950s at ArmaLite, then a division of the Fairchild Aircraft Corporation...

, its predecessor, and the Stoner 63
Stoner 63
The Stoner 63, also known as the XM22/E1, is an American modular weapons system designed by Eugene Stoner in the early 1960s. It was produced by Cadillac Gage and used in very limited numbers in Vietnam by members of the United States Navy SEALs and several law enforcement...

, its rival. In order to compete with the Stoner 63 which could be converted into a belt-fed light or medium machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....

, Colt also included the short-lived CMG-1 and CMG-2
Colt CMG-1 machine gun
The Colt Machine Gun-1 or CMG-1 was an open bolt belt-fed machine gun that fired 5.56x45mm cartridges designed by Colt Manufacturing Company in 1965. Colt hastily developed the CMG-1 to complement the CAR-15, a Colt branding of the M16 rifle, so that Colt might offer both of them as an alternative...

 machine guns in the CAR-15 Military Weapons System, though the CMG-1 and CMG-2 had few parts in common with the CAR-15s. By using various upper assemblies, buttstocks, and pistol grip
Pistol grip
On a firearm or other tool, the pistol grip is that portion of the mechanism that is held by the hand and orients the hand in a forward, vertical orientation, similar to the position one would take with a conventional pistol such as the M1911....

s, the weapon could be configured as an assault rifle, a heavy-barreled automatic rifle
Automatic rifle
Automatic rifle is a term generally used to describe a semi-automatic rifle chambered for a rifle cartridge, capable of delivering both semi- and full automatic fire...

, a carbine, a submachine gun
Submachine gun
A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...

, or as a survival rifle.

Each variation had a Colt model number, meant for internal identification usage. The members of the CAR-15 family, with the exception of the Rifle and Commando, only existed as toolroom
Toolroom
The term toolroom can refer to three related concepts. The concepts have evolved over the past two centuries as technology itself has evolved.- Storing tools :...

 prototypes and never entered full-scale production. As a result, wide variation due to experimentation exists within each model. The U.S. military only made significant purchases of the Rifle and Commando versions, so Colt abandoned the CAR-15 family concept. The CAR-15 Rifle was already identified by most users as M16s or AR-15s, and the CAR-15 name was similarly associated with the short-barreled Submachine Gun and Commando models. Because of that, the term "CAR-15" has been used to describe any M16-based carbine, even if the particular weapon is not officially named thus.

CAR-15 Rifle

The Model 603 CAR-15 Rifle, adopted initially by the United States 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...

 as the XM16E1 and then later as the M16A1, and the Model 604 CAR-15 Rifle, adopted by the United States Air Force
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...

 as the M16, formed the core of the CAR-15 family. However, the United States military had already committed to purchases before Colt created the concept of the CAR-15 weapons system. The principal difference between the Model 603 and Model 604 is that the former has a forward assist
Forward assist
The forward assist on a rifle is a button found commonly on M16 and AR-15 styled rifles, usually located near the bolt closure, that when hit will push the bolt carrier forward, ensuring that the bolt is locked. In order to ensure that the extractor is clipped around the rim of the shell, the...

, allowing a user to manually close the bolt
Bolt (firearm)
A bolt is a mechanical part of a firearm that blocks the rear of the chamber while the propellant burns.In manually-operated firearms, such as bolt-action, lever-action, and pump-action rifles and shotguns, the bolt is held fixed by its locking lugs during firing, forcing all the expanding gas...

.

CAR-15 Carbine

The Model 605A CAR-15 Carbine
Carbine
A carbine , from French carabine, is a longarm similar to but shorter than a rifle or musket. Many carbines are shortened versions of full rifles, firing the same ammunition at a lower velocity due to a shorter barrel length....

 was a shortened version for situations where longer weapons could be unwieldy, such as aboard vehicles or helicopter
Helicopter
A 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. The only significant change from the M16 rifle was that the barrel was shortened to 15 inches in length, so that it ended just forward of the front sight base. Because of the shorter barrel, no bayonet
Bayonet
A bayonet is a knife, dagger, sword, or spike-shaped weapon designed to fit in, on, over or underneath the muzzle of a rifle, musket or similar weapon, effectively turning the gun into a spear...

 mounting lugs were provided. One prototype used a shorter handguard and a 16-inch long barrel.

The Model 605B had no forward assist, but had a four-position selector switch (developed by Foster Sturtevant in December 1966) so that a user could select safe, semi-automatic, three-round burst, or full automatic modes of fire. Unlike the standard three-position group, the four-position group went from (going clockwise from the 9 o'clock position) safe, fully automatic, semi-automatic and finally burst. The selector itself had 360 degrees of motion, and could be moved either clockwise or counterclockwise, unlike with standard groups. Instead of three-round burst, the burst cam could be modified to two-round or six-round burst. Both versions used the rifle-length buttstock.

As early as 1962, United States Navy SEALs
United States Navy SEALs
The United States Navy's Sea, Air and Land Teams, commonly known as Navy SEALs, are the U.S. Navy's principal special operations force and a part of the Naval Special Warfare Command as well as the maritime component of the United States Special Operations Command.The acronym is derived from their...

 were using the CAR-15 Carbine.

CAR-15 Heavy Assault Rifle

The Model 606 CAR-15 Heavy Assault Rifles used heavy barrels (HBAR) for sustained automatic fire. Like the Browning Automatic Rifle (BAR), the CAR-15 HBARs did not have a quick-change barrel. The HBARs could be fitted with either a Colt bipod
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...

, a M14 rifle
M14 rifle
The M14 rifle, formally the United States Rifle, 7.62 mm, M14, is an American selective fire automatic rifle firing 7.62x51mm NATO  ammunition. It was the standard issue U.S. rifle from 1959 to 1970. The M14 was used for U.S...

 M2 bipod, or a modified BAR bipod.

CAR-15 Heavy Assault Rifle M1

The CAR-15 Heavy Assault Rifle M1 used 20-round M16 box magazines, which limited its ability to provide sustained rates of automatic fire. The 30-round M16 box magazine was not available until 1969. The Model 606A had a forward assist. The Model 606B had a forward assist and the four-position selector. The Army purchased fewer than 200 Heavy Assault Rifle M1s for use in the Small Arms Weapons Systems (SAWS) tests in 1965.

CAR-15 Heavy Assault Rifle M2

The CAR-15 Heavy Assault Rifle M2 was a belt-fed version using heavily modified upper and lower receivers. Colt engineer Rob Roy designed a special ammunition box to hold a 50-round or 120-round ammunition belt as well as the expended links. The belt-fed CAR-15 was similar to the belt-fed AR-10 developed by Eugene Stoner
Eugene Stoner
Eugene Morrison Stoner is the man most associated with the design of the AR-15, which was adopted by the US military as the M16...

 and John Peck at ArmaLite. The Army evaluated its use as a helicopter door machine gun but rejected it, so less than 20 of the Heavy Assault Rifle M2s were made.

CAR-15 Submachine Gun

The Model 607 CAR-15 Submachine Gun (SMG) was a compact weapon for use by special forces
Special forces
Special forces, or special operations forces are terms used to describe elite military tactical teams trained to perform high-risk dangerous missions that conventional units cannot perform...

 and vehicle crewmen. The dictionary definition of submachine gun
Submachine gun
A submachine gun is an automatic carbine, designed to fire pistol cartridges. It combines the automatic fire of a machine gun with the cartridge of a pistol. The submachine gun was invented during World War I , but the apex of its use was during World War II when millions of the weapon type were...

 is an automatic firearm that fires pistol-caliber cartridges. However, manufacturers such as Colt
Colt's Manufacturing Company
Colt's Manufacturing Company is a United States firearms manufacturer, whose first predecessor corporation was founded in 1836 by Sam Colt. Colt is best known for the engineering, production, and marketing of firearms over the later half of the 19th and the 20th century...

, Heckler & Koch
Heckler & Koch
Heckler & Koch GmbH is a German defense manufacturing company that produces various small arms. Some of their products include the SA80, MP5 submachine gun, G3 automatic rifle, the G36 assault rifle, the HK 416, the MP7 personal defense weapon, the USP series of handguns, and the high-precision...

, and Zastava Arms
Zastava Arms
Zastava Arms is a Serbian manufacturer of firearms and artillery. It was founded in 1853 when it cast its first cannons. It is currently the leading producer of firearms in Serbia and is a large contributor to the local defence industry...

 have referred to compact carbines as submachine guns, to emphasize their short length and to differentiate them from longer carbines.

The CAR-15 SMG was the first AR-15 made with a retractable buttstock, with its overall length being only 26 inches with the buttstock retracted. The retractable buttstock resembled a shortened version of the fixed buttstock, but a two-position latch recessed in the back allowed it to be extended and locked into position, increasing the length of pull by 2.7 inches. The barrel is too short to mount a bayonet, so the SMG had no bayonet lug.

About 50 CAR-15 SMGs were made. Most were issued to Navy SEALs and Army Special Forces, though some were also given to Army K-9 units. Since it never went into full production, CAR-15 SMGs were assembled from available spare parts. The first models were made with M16 receivers without forward assists and with shortened pistol grips from the Survival Rifle (see below). The later Model 607As were made with XM16E1 receivers with forward assists and standard pistol grips. The handguards were made from full-length rifle handguards by cutting them in half and using either the fore or aft pair, after machining the ends to fit the slip ring and handguard cap.

Because of the short barrel, the CAR-15 SMGs suffered from a loud and bright muzzle blast, and a number of muzzle devices were developed to reduce this. The SMGs were initially fitted with the standard M16 rifle's "duckbill" or three-prong flash hiders, which did not alleviate the problem. In September 1966, Colt developed a 3.5-inch long moderator that lessened the noise and muzzle flash, which also increased the weapon's reliability by increasing the amount of back pressure. However, the moderator created its own problems, such as heavy bore fouling and causing tracer bullets to wildly yaw. A 4.25-inch long moderator with six slots and an expansion chamber, which further reduced noise and flash, replaced the previous muzzle device and became standard for the SMG and the Commando series, but fouling and tracer problems persisted.

CAR-15 Survival Rifle

The Model 608 CAR-15 Survival Rifle was meant for use by downed aircrew. Because of the CAR-15's modular design, the Survival Rifle could be broken down into two subassemblies and stowed with four 20-round magazines in a pilot's seat pack. With only a 10-inch long barrel, the assembled weapon was 29 inches in overall length. The Survival Rifle used a fixed tubular plastic-coated aluminum buttstock and a round handguard that were not used on the other CAR-15 versions, and did not have either a forward assist or a bayonet lug. The pistol grip was chopped down, and the muzzle was equipped with either a conical flash hider
Flash suppressor
A flash suppressor, also known as a flash guard, flash eliminator, flash hider, or flash cone, is a device attached to the muzzle of a rifle or other gun that reduces the visible signature of the burning gases that exit the muzzle. This reduces the chances that the shooter will be blinded in dark...

 or the 3.5-inch long moderator.

CAR-15 Commando (XM177/GAU-5 series)

The CAR-15 Commando was not initially part of the CAR-15 Military Weapons System, but was added in 1966 in response to the US military's desire for a shorter M16 and the Model 607 SMG's inadequacies. Colt engineer Rob Roy designed a simpler two-position telescoping tubular aluminum buttstock to replace the complicated extending triangular version. The fragile and ad hoc triangular handguards were replaced by reinforced round handguards. Each half of the round handguard was identical, simplifying logistics by not requiring a top/bottom or left/right pair. The Model 609 Commando had a forward assist, while the Model 610 Commando did not. A Model 610B with a four-position selector was available, but not used by the U.S. military. All versions were equipped with the 4.25-inch long moderator.

The Model 610 was classified as the XM177 but adopted by the Air Force as the GAU-5/A Submachine Gun (GAU = Gun, Aircraft, Unit.) The Army purchased 2,815 Model 609 CAR-15 Commandos on June 28, 1966, which were officially designated Submachine Gun, 5.56 mm, XM177E1. As part of the contract, Colt was supposed to supply each XM177E1s with seven 30-round magazines, but Colt was unable to build a reliable 30-round curved magazine that would fit in the M16 magwell, so most XM177E1s were shipped with 20-round magazines. The exception was 5th Special Forces Group, who received a total of four early 30-round magazines. Colt completed delivery of the purchased XM177E1s in March 1967.

In 1967, in response to field testing, Colt lengthened the Commando's barrel from 10 inches to 11.5 inches. The increased length reduced noise and muzzle flash, and allowed fitting of the Colt XM148 grenade launcher. A metal boss was added to the moderator for mounting of the XM148 and rifle grenade
Rifle grenade
A rifle grenade is a grenade that uses a rifle-based launcher to permit a longer effective range than would be possible if the grenade was thrown by hand...

s. The chambers were chrome-plated. The Commandos with the longer barrels were called the Model 629 and Model 649. The Model 629 Commando had a forward assist; the Model 649 Commando did not.

In April 1967, the Army purchased 510 Colt 629 Commandos for use by troops assigned to the Military Assistance Command, Vietnam Studies and Observations Group
Military Assistance Command, Vietnam Studies and Observations Group
Military Assistance Command, Vietnam – Studies and Observations Group was a highly classified, multi-service United States special operations unit which conducted covert unconventional warfare operations prior to and during the Vietnam War....

 (MACV-SOG), and designated them XM177E2. Delivery was completed by the end of September 1967. The Air Force adopted a similar model without the forward assist feature as the GAU-5A/A. Sources debate whether or not this was a Colt Model 630 or 649. According to John Plaster
John Plaster
Major John L. Plaster is a former U.S. Army Special Forces soldier regarded as one of the leading sniper experts in the world. A decorated Vietnam War veteran who served in the covert Studies and Observations Group , Plaster co-founded a renowned sniper school that trains military and law...

 and other sources, the lack of 30 round magazines continued to be problematic and SOG operators resorted to pooling their personal resources and purchasing the larger capacity magazines on the civilian U.S. market. Problems with range, accuracy, barrel fouling, and usage of tracer bullets continued to plague the XM177 series, but Colt estimated that it would take a six-month $400,000 program to do a complete ballistic and kinematic study. There were also recommendations for a 29-month $635,000 research and development program. Both recommendations were declined by the U.S. military as American ground force involvement in the Vietnam War was gradually winding down. Production of the CAR-15 Commando ended in 1970.

Post-Vietnam

After the Vietnam War, Colt abandoned the CAR-15 Military Weapons System concept, but continued to develop heavy-barreled rifles, carbines, and Commandos for military use. These were marketed under the M16 or M16A1 name, while the civilian and law-enforcement semi-automatic
Semi-automatic rifle
A semi-automatic rifle is a type of rifle that fires a single bullet each time the trigger is pulled, automatically ejects the spent cartridge, chambers a fresh cartridge from its magazine, and is immediately ready to fire another shot...

 counterparts were marketed as AR-15s.

In the mid-1970s, the Bureau of Alcohol, Tobacco, and Firearms (BATF) declared the 4.25-inch long moderator a sound suppressor
Suppressor
A suppressor, sound suppressor, sound moderator, or silencer, is a device attached to or part of the barrel of a firearm which reduces the amount of noise and flash generated by firing the weapon....

. During the Carter Administration, the U.S. State Department
United States Department of State
The United States Department of State , is the United States federal executive department responsible for international relations of the United States, equivalent to the foreign ministries of other countries...

 banned the sale of sound suppressors to foreign countries. Colt therefore designed carbines without the moderator.

Colt Model 653 M16A1 Carbine

In the early 1970s, Colt began development of an M16A1 carbine with a 14.5-inch long barrel. The 14.5-inch length was compatible with the existing carbine-length gas system and allowed for the mounting of a standard M16 bayonet. Despite having a longer barrel, it would not be less compact than the previous carbines. Depending on whether it had a fixed or retractable buttstock and a forward assist, Colt labeled the M16A1 carbines the Model 651, 652, 653, or 654. All models used the M16A1 birdcage flash hider. Only the Model 653 M16A1 carbine, with retractable buttstock and forward assist would be purchased in significant numbers by the U.S. military. The United States Army, Navy and Air Force, as well as the Malaysian Armed Forces, purchased Model 653s in small numbers for special operations forces or security forces.

During the Yom Kippur War
Yom Kippur War
The Yom Kippur War, Ramadan War or October War , also known as the 1973 Arab-Israeli War and the Fourth Arab-Israeli War, was fought from October 6 to 25, 1973, between Israel and a coalition of Arab states led by Egypt and Syria...

, the American government sent arms and equipment, including Model 653s, to the Israeli Defense Forces
Israel Defense Forces
The Israel Defense Forces , commonly known in Israel by the Hebrew acronym Tzahal , are the military forces of the State of Israel. They consist of the ground forces, air force and navy. It is the sole military wing of the Israeli security forces, and has no civilian jurisdiction within Israel...

 as part of Operation Nickel Grass
Operation Nickel Grass
Operation Nickel Grass was an overt strategic airlift operation conducted by the United States to deliver weapons and supplies to Israel during the Yom Kippur War. The Military Airlift Command of the U.S...

. These Model 653s, which have been called "CAR-15s" by its users, continue to be in use with the IDF today. Some of the Model 653s in Israeli service have been heavily customized over the service years, such as having the barrel replaced or chopped down in length. They have been nicknamed Mekut'zar or Mekut'zrar. They are slowly being replaced with/or revamped to M4 carbine
M4 carbine
The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter variant of the M16A2 assault rifle, with 80% parts commonality.It is a gas-operated,...

s. Colt also licensed Elisco Tools to produce the M16A1 carbine in the Philippines, who became a major user of the type, as the Model 653P.

M4 Carbine

In the early 1980s, at the request of the United States Marine Corps, Colt upgraded the M16A1 rifle, resulting in the M16A2 rifle. Among the major changes were a reinforced lower receiver, a case deflector, a birdcage flash suppressor redesigned to be a muzzle brake, and a barrel with a faster 1-in-7 twist. The faster barrel was necessitated by the switch from the 55 grain M193 bullet to the 62 grain M855 bullet. The M16A2 rifle's barrel was also thicker for the portion in front of the handguard. Colt incorporated these changes into its carbines, which it called M16A2 carbines. The Model 723 M16A2 carbine used the iron sights of the M16A1, but had a case deflector. The barrel had a 1-in-7 twist, but the thinner profile of the older M16A1 carbine's barrel. As with the Model 653, the United States military made small purchases of the Model 723 for its special operation forces.

In 1983, Diemaco
Diemaco
Diemaco was a Canadian defense company based in Kitchener, Ontario, Canada, that manufactured the C7 family of rifles under a licence from Colt. It was acquired by Colt on May 20, 2005, in a $18.2 million purchase from parent company Héroux-Devtek Inc, which had purchased Diemaco in 2000....

 developed a carbine similar to the Model 723, the C8 carbine for use by the Canadian Forces
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 original C8s were built by Colt as the Model 725.

In 1984, the United States government asked Colt to develop a carbine with maximum commonality with the issue M16A2. Colt named the carbine as the XM4. The project would eventually culminate in the official adoption of the M4 carbine
M4 carbine
The M4 carbine is a family of firearms tracing its lineage back to earlier carbine versions of the M16, all based on the original AR-15 designed by Eugene Stoner and made by ArmaLite. It is a shorter and lighter variant of the M16A2 assault rifle, with 80% parts commonality.It is a gas-operated,...

 in 1994.

The United Arab Emirates
United Arab Emirates
The United Arab Emirates, abbreviated as the UAE, or shortened to "the Emirates", is a state situated in the southeast of the Arabian Peninsula in Western Asia on the Persian Gulf, bordering Oman, and Saudi Arabia, and sharing sea borders with Iraq, Kuwait, Bahrain, Qatar, and Iran.The UAE is a...

 (U.A.E.) wished to purchase M16A2 carbines with the thicker M16A2 barrel, but still be able to mount the M203 grenade launcher
M203 grenade launcher
The M203 is a single shot 40 mm grenade launcher designed to attach to a rifle. It uses the same rounds as the older M79 break-action grenade launcher, which utilize the High-Low Propulsion System to keep recoil forces low. Though versatile, and compatible with many rifle models, the M203 was...

. The M203 grenade launcher was designed for the thinner M16A1 barrel. A "step-cut" barrel was made, with a portion of the barrel thinned for the M203 mount. M16A2 carbines with A2 upper receivers and the step-cut barrel were designated Model 727. These are often called "Abu Dhabi" carbines, in reference to the capital
Abu Dhabi
Abu Dhabi , literally Father of Gazelle, is the capital and the second largest city of the United Arab Emirates in terms of population and the largest of the seven member emirates of the United Arab Emirates. Abu Dhabi lies on a T-shaped island jutting into the Persian Gulf from the central western...

 of the U.A.E. The U.S. military also purchased several of these carbines prior to the official adoption of the M4.

GUU-5/P

The United States Air Force has made ad hoc upgrades to its GAU-5/As and GAU-5A/As. The barrels and moderators were replaced with the longer 14.5-inch barrel with a 1-in-12 twist, but the weapons retained their original designations. With the change to M855 cartridges, they either received 1-in-7 twist barrel or complete upper receiver assembly replacements. The GAU-5/A or GAU-5A/A markings were removed and the weapons redesignated GUU-5/P. They also retain automatic fire instead of burst.

The new designation more accurately reflected the weapon's place in the U.S. Air Force Aerospace Equipment Type Designation System (AETDS). The weapons had initially been designated in the same format as aircraft guns, being placed in the GA category (GA designating an aircraft gun, with U meaning unit, representing a complete system and not part of a kit), followed by the /A suffix meaning the system was for aircraft. GUU is the "guns, miscellaneous personal equipment" category, and the /P suffix indicating personal equipment.

Colt Commando

Though Colt has focused its attention on carbines with 14.5-inch barrels and rifles with 20-inch barrels, Colt continues to make carbines with 11.5-inch barrels, which it calls Commandos. Commandos are assembled from whatever spare parts are available, so Model 733 Commandos can have A1-style upper receivers, A1-style upper receivers with case deflectors, or A2-style upper receivers, and M16A1-profile 1:7 or M16A2-profile 1:7 barrels. Depending on the specific models, current Commandos may have three-position fire control groups (safe/semi-automatic/three-round burst), or four-position having both full-automatic and burst. The Model 933 has a "flattop" receiver, with a removable carrying handle and a MIL-STD-1913 Picatinny rail
Picatinny rail
The Picatinny rail or MIL-STD-1913 rail or STANAG 2324 rail or a "Tactical Rail" is a bracket used on some firearms in order to provide a standardized mounting platform. A similar system is the Weaver rail mount.-Description:...

. Though originally called the M16A2 Commando, Colt now markets it as the M4 Commando.

Some American special operation forces, such as Army Special Operation Groups, use the M4 Commando in a limited capacity. Marine Force Recon
United States Marine Corps Force Reconnaissance
The Force Reconnaissance Companies , are one of the United States Marine Corps's special operations "capable" forces that provide essential elements of military intelligence to the command element of the Marine Air-Ground Task Force ; supporting the landing or joint task force commanders, and...

 personnel sometimes use M4 Commandos in place of their US M9 pistols
M9 Pistol
The Beretta M9, formally Pistol, Semiautomatic, 9mm, M9, is a 9×19mm Parabellum pistol of the United States military adopted in 1985. It is essentially a military specification Beretta 92F, later the 92FS....

.

The Colt Commando's 11.5-inch barrel creates a substantially lower muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

 and greater muzzle flash, in comparison to longer M16 carbines and rifles. The lower muzzle velocity may reduce wounding effects. In 2005, Colt came out with a semi auto only version of the 733. The designation of this rifle is the 6933.

Recently, the Mk 18 Mod 0 with a 10.3-inch barrel has taken the role of ultracompact carbine with the U.S. Navy SEALs
United States Navy SEALs
The United States Navy's Sea, Air and Land Teams, commonly known as Navy SEALs, are the U.S. Navy's principal special operations force and a part of the Naval Special Warfare Command as well as the maritime component of the United States Special Operations Command.The acronym is derived from their...

.

Further reading

  • Ezell, Edward. Small Arms Today, 2nd Edition. Harrisburg, PA: Stackpole Books, 1988. ISBN 0-8117-2280-5.
  • Gervasi, Tom. Arsenal of Democracy III: America's War Machine, the Pursuit of Global Dominance. New York, NY: Grove Press, Inc, 1984. ISBN 0-394-54102-2.
  • Plaster, John. Secret Commandos: Behind Enemy Lines with the Elite Warriors of SOG Penguin Books, 2004. ISBN 0-451-21447-1

External links

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