Colt CMG-1 machine gun
Encyclopedia
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 to the Stoner 63
weapons system. It failed to achieve any sales, and was replaced by the Colt CMG-2, which also failed to achieve any sales.
Though marketed together with the CAR-15, the CMG-1 had few parts in common with it. One CMG-1 used direct impingement
and shared the bolt, gas tube, and other operating parts of the M16. However, other CMG-1s used gas pistons
. The CMG-1s also used the M16's pistol grip
, front sight block, and flash hider
. Similar to the Stoner 63, the CMG-1 could be fed from either side. The rate of fire was 650 rounds per minute. Only two or three CMG-1s were ever made. Colt made them with sheet-metal stamping.
Colt offered the CMG-1 in four different versions: bipod-mounted, tripod-mounted, vehicle-mounted, or fixed mount. The 11.5 lb (5.2 kg). bipod-mounted
version was marketed as a light machine gun for use by assault troops. It was the only version with a buttstock. The 12.5 lb (5.7 kg). tripod-mounted
version was considered a medium machine gun. The vehicle mounted version was a pintle-mounted
machine gun for use by soldiers in land vehicles. The fixed mount version was fired by a solenoid allowing for remote operation so it could be mounted in a helicopter or other aircraft.
In 1967, Colt replaced the CMG-1 with the CMG-2. The CMG-2 abandoned any commonality with the M16 and was only available as a bipod-mounted light machine gun with a vertical foregrip. It was fed from a 150-round belt using S-63 link contained in a drum
. The CMG-2 was gas-piston operated, but used an M16 bolt. The extractor was machined into the bolt. The CMG-2's barrel was detachable and had a handle, so an overheated barrel could be replaced in the field. The barrel had a 1:9 twist and was meant to fire an experimental 68 gr bullet, designed for longer ranges than the then-standard 55 gr M193 bullet. Unlike the M60 machine gun
, then in use in the Vietnam War
, an M2 bipod was mounted on the CMG-2's ventilated handguard. The most unusual feature was that a user charged the CMG-2 by unlocking the pistol grip, and then sliding it forward and back. Colt submitted a buttstock-less short-barreled CMG-2 to the Navy SEALs
. The Navy classified the CMG-2 as the EX 27 Mod 0 machine gun but they ultimately chose the Stoner 63 MK23 Mod 0 Commando
instead. The CMG-2 never left prototype phase and Colt ceased development in 1969.
Open bolt
A semi or full automatic firearm is said to fire from an open bolt if, when ready to fire, the bolt and working parts are held to the rear. When the trigger is pulled the bolt goes forward, feeding a round from the magazine into the chamber and firing it...
belt-fed
Belt (firearm)
A belt or ammunition belt is a device used to retain and feed cartridges into a firearm. Belts and the associated feed systems are typically employed to feed machine guns or other automatic weapons...
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....
that fired 5.56x45mm cartridges
5.56 x 45 mm NATO
5.56×45mm NATO is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge...
designed by Colt Manufacturing Company in 1965. Colt hastily developed the CMG-1 to complement the CAR-15
CAR-15
The Colt Automatic Rifle-15 Military Weapons System or CAR-15 was a family of AR-15 and M16 rifle–based firearms marketed by Colt 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...
, a Colt branding of the 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...
, so that Colt might offer both of them as an alternative to 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...
weapons system. It failed to achieve any sales, and was replaced by the Colt CMG-2, which also failed to achieve any sales.
Though marketed together with the CAR-15, the CMG-1 had few parts in common with it. One CMG-1 used direct impingement
Direct impingement
Direct impingement is a type of gas operation for a firearm that directs gas from a fired cartridge directly to the bolt carrier or slide assembly to cycle the action.- Evaluation :...
and shared the bolt, gas tube, and other operating parts of the M16. However, other CMG-1s used gas pistons
Gas-operated reloading
Gas-operation is a system of operation used to provide energy to operate autoloading firearms. In gas-operation, a portion of high pressure gas from the cartridge being fired is used to power a mechanism to extract the spent case and chamber a new cartridge. Energy from the gas is harnessed...
. The CMG-1s also used the M16's 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....
, front sight block, and 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...
. Similar to the Stoner 63, the CMG-1 could be fed from either side. The rate of fire was 650 rounds per minute. Only two or three CMG-1s were ever made. Colt made them with sheet-metal stamping.
Colt offered the CMG-1 in four different versions: bipod-mounted, tripod-mounted, vehicle-mounted, or fixed mount. The 11.5 lb (5.2 kg). bipod-mounted
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:...
version was marketed as a light machine gun for use by assault troops. It was the only version with a buttstock. The 12.5 lb (5.7 kg). tripod-mounted
Tripod
A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the...
version was considered a medium machine gun. The vehicle mounted version was a pintle-mounted
Pintle
A pintle is a pin or bolt, usually inserted into a gudgeon, which is used as part of a pivot or hinge.A pintle/gudgeon set is used in many spheres, for example: in sailing to hold the rudder onto the boat; in transportation a pincer-type device clamps through a lunette ring on the tongue of a...
machine gun for use by soldiers in land vehicles. The fixed mount version was fired by a solenoid allowing for remote operation so it could be mounted in a helicopter or other aircraft.
In 1967, Colt replaced the CMG-1 with the CMG-2. The CMG-2 abandoned any commonality with the M16 and was only available as a bipod-mounted light machine gun with a vertical foregrip. It was fed from a 150-round belt using S-63 link contained in a drum
Drum magazine
A drum magazine is a type of firearms magazine that is cylindrical in shape, similar to a drum. Instead of rounds being stored flat, as in a more common box magazine, rounds in a drum magazine are stored in a spiral around the center of the magazine, facing the direction of the barrel.There are...
. The CMG-2 was gas-piston operated, but used an M16 bolt. The extractor was machined into the bolt. The CMG-2's barrel was detachable and had a handle, so an overheated barrel could be replaced in the field. The barrel had a 1:9 twist and was meant to fire an experimental 68 gr bullet, designed for longer ranges than the then-standard 55 gr M193 bullet. Unlike the M60 machine gun
M60 machine gun
The M60 is a family of American general-purpose machine guns firing 7.62×51mm NATO cartridges from a disintegrating belt of M13 links...
, then in use in 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...
, an M2 bipod was mounted on the CMG-2's ventilated handguard. The most unusual feature was that a user charged the CMG-2 by unlocking the pistol grip, and then sliding it forward and back. Colt submitted a buttstock-less short-barreled CMG-2 to the 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...
. The Navy classified the CMG-2 as the EX 27 Mod 0 machine gun but they ultimately chose the Stoner 63 MK23 Mod 0 Commando
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...
instead. The CMG-2 never left prototype phase and Colt ceased development in 1969.