Armalite AR-10

AR-10
The AR-10 at the National Firearms Museum
Type	Battle Rifle
Place of origin	United States
Service history
In service	1960–1976 (Portugal) 1958–1985 (Sudan)
Used by	See AR-10 purchasers by country
Wars	Portuguese Colonial War Angolan Independence War Mozambican War of Independence Vietnam War Portuguese Timor Conflict
Production history
Designer	Eugene Stoner
Manufacturer	ArmaLite Artillerie Inrichtingen (AI) Colt's Manufacturing Company
Produced	1956–present
No. built	9,900
Specifications
Weight	3.29–4.05 kg (7.25–8.9 lb) w/o magazine
Length	1,050 mm (41.3 in)
Barrel length	528 mm (20.8 in)
Cartridge	7.62×51mm NATO .308 Winchester
Action	Direct impingement, rotating bolt
Rate of fire	700 rounds/min (fully automatic), variable (semi-automatic)
Muzzle velocity	820 m/s (2,690 ft/s)
Effective firing range	600m/656yd (ca 700m/765 1/2yds with A.I. 3.6× telescopic sight)
Feed system	20-round detachable box magazine
Sights	Adjustable aperture rear sight, fixed post front sight

The AR-10 is a 7.62×51mm NATO battle rifle developed by Eugene Stoner in the late 1950s at ArmaLite, then a division of the Fairchild Aircraft Corporation. When first introduced in 1956, the AR-10 used an innovative straight-line barrel/stock design with phenolic composite and forged alloy parts resulting in a small arm significantly easier to control in automatic fire and over 1 lb (0.45 kg) lighter than other infantry rifles of the day. Over its production life, the original AR-10 was built in relatively small numbers, with fewer than 9,900 rifles assembled.

In 1957, the basic AR-10 design was rescaled and substantially modified by ArmaLite to accommodate the .223 Remington cartridge, and given the designation ArmaLite AR-15. ArmaLite licensed the AR-10 and AR-15 designs to Colt Firearms. The AR-15 eventually became the M16 rifle.

ArmaLite began as a small engineering concern founded by George Sullivan, the patent counsel for Lockheed Corporation, and funded by Fairchild Engine and Airplane Corporation. On October 1, 1954, the company was incorporated as the ArmaLite Corporation, becoming a subdivision of Fairchild. With its limited capital and tiny machine shop, ArmaLite was never intended to be an arms manufacturer. The company focused on producing small arms concepts and designs to be sold or licensed to other manufacturers. Sullivan leased a small machine shop at 6567 Santa Monica Boulevard in Hollywood, California, hired several employees, and began work on a prototype for a lightweight survival rifle for use by downed aircrew.

While testing the prototype of the Armalite AR-5 survival rifle design at a local shooting range, Sullivan met Eugene Stoner, a talented small arms inventor, whom Sullivan immediately hired to be ArmaLite's chief design engineer. At the time, ArmaLite Inc. was a very small organization (as late as 1956 it had only nine employees, including Stoner). With Stoner as chief design engineer, ArmaLite quickly released a number of interesting rifle concepts.