The Colt Machine Gun (abbreviated CMG) was a prototype series of three American machine guns designed from 1965 to the early 1970s and marketed by Colt's Manufacturing Company. Marketed alongside the M16, the CMG attempted to compete against the Stoner 63 weapon system; while a decent weapon, the project ended up being unsuccessful and the weapon was not developed further.
History[]
The CMG was designed in 1965 as Colt's attempt to capitalize on the sales of the M16 by offering a companion machine gun; the company felt that the cartridge parity would help to increase the sales of both weapons.
Colt's first attempt was known as the CMG-1; it shared some parts commonality with the M16 and could be adapted to a number of different roles. Despite all this commonality, the weapon failed to sell and never exited the prototype stage. Somewhere in the region of two or three were produced.[1]
Not wanting to waste potential on a weapon system they had just developed, Colt redesigned the CMG-1 entirely in 1967 to become the CMG-2, the second iteration of the weapons system. The CMG-2 removed any and all parts commonality between it and the M16 and added a number of features not present on the CMG-1, such as a foregrip. The weapon was sent for trials by the U.S. Navy SEALs, where it was trialed against the Stoner 63 weapon system; while both were excellent guns, the CMG-2 was considered inferior to the Stoner 63 and rejected. It is estimated between twenty-seven and thirty were produced.[1]
The CMG was redesigned one last time in the 1970s; in response to a request for proposal for a lightweight .308 caliber machine gun for special operations troops, Colt designed the CMG-3, the final iteration of the Colt Machine Gun. Five copies of the weapon were made and were tested by the U.S. Navy once again; however, the weapon rejected on account of the its long-term durability not being up to par with the U.S. Navy's standards (they determined the receiver would only last 35,000 rounds compared to their standard of 100,000), as it was noted that a portion of the receiver underneath the barrel attachment would crack under prolonged firings.[2] When Colt finally figured out how to correct these issues, testing was over and the proposals had lapsed.[3][2] Three of the five CMG-3s were destroyed during testing, with only two known to exist today.[1]
Design Details[]
The CMG-1 shared a lot in common mechanically with the M16 which it was marketed with, utilizing an expanding gas piston, similar to that of an M16; the CMG-1 also has dual feed functionality, allowing it to feed from both the right and left hand side. The CMG-2, however, uses simple gas operation.
The CMG is notable for having a reversible firing pin which allows the other end to be used in case one end breaks off. The weapon's gas block is located under the barrel. The weapon uses an M14 bipod. The weapon is also notable for having a "broom-type" ejector, which is a lever which flicks cartridges down and out of the weapon by sweeping across the bolt face.
The CMG's top cover has a spring which aids in pushing rounds into the chamber nose-down; a lug is present on the top of the bolt to assist in the feeding cycle. When the gun cycles, the lug drags one cartridge out of the belt, strips the link, with the cover spring pushing the cartridge down into battery. After the gun fires, the ejector throws the spent cartridge down out of the weapon.[1] The weapon is noted as having a controlled round feed.[4]
The weapon has a quick change barrel; the CMG-3's barrel is held in by a latch, which when pushed allows the barrel to be removed.[2] The weapon feeds from a 150-round belt box with an enclosed feed channel, which made reloading slightly more difficult when compared to the Stoner 63 it competed with.[1] The weapon's pistol grip acts as the charging handle, with the pistol grip pushed forward, then backwards to charge the weapon.[2]
Variants[]
The CMG design was changed a number of times over the course of its development.
- CMG-1
Original design. Had quick-change barrel and could be adapted to a number of roles.[1] Had dual-feed.
- CMG-1A
Had enlarged bolt and left-side feed only.
- CMG-2
First refinement of the CMG design. Ditched parts commonality with the M16 and added improvements.[1]
- CMG-3
7.62mm NATO version of the CMG-2. Designed as a result of a request for proposal for a light 7.62mm machine gun; rejected on lack of reliability.[1]
References[]
- ā 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 http://www.historicalfirearms.info/post/101960250566/colt-cmg-series-the-colt-machine-gun-project-was/embed
- ā 2.0 2.1 2.2 2.3 https://youtu.be/g3aayF-S2ps
- ā https://americangg.net/rare-colt-unicorn/
- ā https://www.thefirearmblog.com/blog/2015/09/20/designed-right-the-colt-cmg-3/