Armalite AR-18

ArmaLite AR-18
The ArmaLite AR-18
Type	Rifle
Place of origin	United States
Service history
Used by	See Users
Production history
Designer	Eugene Stoner (AR-16) Arthur Miller
Designed	1963
Manufacturer	ArmaLite (U.S.) HOWA Machinery Co. (Japan) Sterling Armaments Company. (UK)
Produced	1969–1985
Variants	AR-18K AR-18S AR-180 AR-180B Foreign derivatives based upon the AR-18 include the British SA-80, Singaporean/British SAR-87 and the Japanese Howa Type 89 Bullpup adaptations include Australian Bushmaster M17S
Specifications
Weight	6.7 lb (3.0 kg) (empty) 7.18 lb (3.3 kg) (loaded w/20 rd. magazine)
Length	38 in (970 mm)
Barrel length	18.25 in (464 mm) (6-groove rifling)
Cartridge	5.56×45mm NATO
Action	Short-stroke piston, rotating bolt
Rate of fire	750 rounds/min
Muzzle velocity	3,250 ft/s (991 m/s)
Feed system	20, 30, or 40-round detachable box magazine
Sights	Iron sights or removable 3× scope

The AR-18 is a gas-operated, selective-fire rifle chambered for 5.56×45mm NATO ammunition. The AR-18 was designed at ArmaLite in California by Arthur Miller, Eugene Stoner, George Sullivan, and Charles Dorchester in 1963 as an alternative to the AR-15 design, which had just been selected by the U.S. military as the M16. While the AR-18 was never adopted as the standard service rifle of any nation, its production licence was sold to companies in Japan and the United Kingdom, and it is said to have influenced many later weapons such as the British SA80, the Singaporean SAR-80 and SR-88, the American Adaptive Combat Rifle, and the Heckler and Koch G36. Through the Provisional IRA, which was noted for its use of the rifle, the rifle became known as the "Widowmaker".

Soon after the adoption of the 7.62×51mm NATO M14 rifle in 1957, the U.S. Army's Continental Army Command (CONARC) began an investigation of small-caliber, high-velocity (SCHV) rifles as an offshoot of the military's existing research program, Project SALVO. ArmaLite and Winchester Arms were solicited by CONARC to provide prototype automatic rifles chambered for high-velocity centerfire .22 rounds. ArmaLite's AR-15 was a scaled-down version of the 7.62mm AR-10, which had appeared too late to be a serious contender against the M14 for adoption by the US Army. Its competitor was the Winchester .224 Light Rifle, a 'Carbine' Williams prototype carbine design in a .22 high velocity round which was similar to, but not interchangeable with, the .223 Remington (5.56×45mm). During the protracted U.S. military trials of the AR-15, ArmaLite's corporate owners Fairchild essentially gave up on the design, and sold the AR-15 production rights to Colt. Fairchild also spun off ArmaLite as an independent company, allowing the new owners to buy all of the company's designs except for the AR-10 and AR-15. When the U.S. military ultimately selected the AR-15 as the M16, ArmaLite could no longer profit from its adoption.