The Largest Security-Cleared Career Network for Defense and Intelligence Jobs - JOIN NOW


M16 5.56mm Rifle


The AR-15/M16 family of weapons is one of the more proliferated small arms types, with dozens of variants and derivatives around the world. It is also widely found among civilian shooters in the United States and elsewhere. In the United States alone its popularity has led to the appearance of dozens of manufacturers and other concerns responsible for producing individual parts and accessories, as well as complete weapons. The number of sources has often led to a confusion in nomenclature between military and civilian types, with terms being reused, modified, or otherwise applied to weapons that do not fit the firm military definitions.

The term AR-15 comes from the original manufacturer of the system, Armalite, which during the 1950s was a division of the Fairchild Aircraft Corporation. The Armalite company had already produced a number of different rifles, including the AR-5 and AR-7 survival rifles, and the 7.62mm AR-10 rifle, designed by Eugene Stoner. The AR-10 was the predecessor to the 5.56mm AR-15 rifle. AR in this commercial nomenclature simply stood for Armalite Rifle. The initial variants acquired by the US military, purchased commercially, did not recieve an Army Type Designation or one from any of the other services. In the US Army nomenclature system, for instance, no official type designator must be applied if the system procured is essentially unmodified from its commercial form. These weapons were known in US service simply as AR-15s.

The origins of some of the most basic confusions began in 1959, with the effective sale of the AR-10 and AR-15 design and trademarks to Colt Firearms. When Armalite split from Fairchild in 1961, it could not recover this transfer. Colt did initially mark its weapons as "Colt-Armalite AR-15s," but the Armalite name was soon dropped. The term AR-15 remained, with Colt retaining effective ownership of the trademark.

In January 1963, the US Army type standardized a variant of the AR-15 featuring among other things a manual bolt closure device (referred to generally as a "forward assist"), which allowed the weapon's action to be closed manually. This weapon became the XM16E1. The nomenclature XM16 was retroactively applied to previous AR-15s in service lacking the bolt-closure feature, but effectively existed only on paper. The XM16 subsequently became the M16, while the XM16E1 became the M16A1.

In May 1964, Colt began an attempt to rebrand the AR-15, and greatly expanded the variants available. The Colt Automatic Rifle 15 (CAR-15) Weapon System family included 2 standard select-fire rifles (the weapons that had been designated as the M16 and M16A1), 2 heavy barreled automatic rifles (including one with a belt-feed system developed by Colt engineer Rob Roy), a carbine (with a 16 inch barrel instead of the normal 20 inch barrel), a short-barrled "submachine gun" (not fitting the generally held technical definition of a submachine gun in that it used rifle ammunition), and a survival rifle. While the US Army tested all the variants, the one that became most associated with the term CAR-15 in the field was the submachine gun variant. The term subsequently became associated with short-barreled variants, though it in fact referred to the entire family of weapons. Colt effectively dropped the term AR-15.

The term AR-15 was revived in the 1980s with changes occuring to US gun control laws. The term was applied to semi-automatic only variants to help seperate them from fully-automatic military variants. Thus in common parlance, AR-15 became a term used to reference semi-automatic variants. The military term M16 became a term used for fully-automatic weapons, regardless of whether they had been converted from civilian variants, were commercial fully-automatic weapons, or were actual surplus US military M16s. Colt also revived the term CAR-15, but used the term largely as it had become understood in common parlance, to refer to semi-automatic short-barreled variants.

Colt also applied the term M16 to all weapons not featuring the improvements made to the weapon's lower reciever (the component housing the fire control components, to which the stock and pistol grip were attached) on what became the US military's M16A2, M16A2 to all weapons featuring the improved lower reciever, and M16A3 to any weapon with a so-called "flat top" upper reciever featuring a MIL-STD-1913 accessory rail. These commercial nomenclatures did not mirror the actual US military nomenclature, causing additional confusion. Manufacturers have subsequently applied the A2 and A3 suffixes to other commercial nomenclature following these conventions, including the term "M4" for carbines, despite no official M4A2 or M4A3 existing.

Join the mailing list

Page last modified: 03-01-2012 16:04:42 ZULU