Type Battle rifle
Place of origin United States
In service 1960–1976 (Portugal)
Used by See Users
Wars Angola, Mozambique, Sudan, Dominican Republic, Portuguese Timor Conflict
Designer Eugene Stoner
Manufacturer Fairchild ArmaLite, Artillerie Inrichtingen (AI)
Number built Approx. 10,000
Weight 3.29–4.05 kg (7.25–8.9 lb)
Length 1,050 mm (41.3 in)
Barrel length 528 mm (20.8 in)
Cartridge 7.62x51mm NATO
Action Gas-operated, rotating bolt
Rate of fire 700 rounds/min
Muzzle velocity 820 m/s (2,690 ft/s)
Effective range 630 m
Feed system 20-round detachable box magazine
Sights Adjustable aperture rear sight, fixed post front sight
The AR-10 is an American 7.62 mm battle rifle developed by Eugene Stoner in the late 1950s at ArmaLite, then a division of the Fairchild Aircraft Corporation. The rifle had some innovative features at the time of its introduction (1956); it was over 1 lb (0.45 kg) lighter than most other infantry rifles, it was significantly easier to control in automatic fire, was more accurate in semi-auto mode, and arguably handled better than any other weapon of the period. The unique features of the AR-10 would eventually be developed into the U.S. Army's M16. Over its production life, the original AR-10 was built in relatively small numbers, with fewer than 10,000 rifles assembled.
ArmaLite first opened as a subdivision of Fairchild in 1954, specifically to bring new materials and designs to the firearms industry. Later that year they were joined by Eugene Stoner, a talented small arms engineer. ArmaLite was a very small organization at the time (only nine employees, including Stoner). With Stoner as chief design engineer, ArmaLite quickly released a number of interesting rifle designs. The first prototypes of the 7.62 mm AR-10 emerged during 1955 and early 1956. At the time the United States Army was in the midst of testing several rifles to replace the obsolescent M1 Garand. Springfield Armory's T44E4 and heavier T44E5 were essentially updated versions of the Garand chambered for the new 7.62 mm round, while Fabrique Nationale submitted their FAL as the T48. ArmaLite's AR-10 entered the competition late, hurriedly submitting two AR-10 rifles in the fall of 1956 to the United States Army's Springfield Armory for testing. The new rifle featured a straight-line stock design, rugged elevated sights, a flash suppressor/recoil compensator, and an adjustable gas system. Initial comments by Springfield Armory test staff were favorable, and some testers commented that the AR-10 was the best lightweight automatic rifle ever tested by the Armory.
Unfortunately for ArmaLite, the rifle's aluminum/steel composite barrel (an untried prototype design specified for the tests by ArmaLite's president, George Sullivan, over Stoner's vehement objections) burst in a torture test conducted by Springfield Armory in early 1957. ArmaLite quickly replaced it with a conventional steel barrel, but the damage had been done. The final Springfield Armory report advised against adoption of the rifle, stating that "it would take five years or more to take it through tests to adoption". While ArmaLite objected, it was clear that the AR-10, a brand-new rifle still in the prototype stage, was at a disadvantage compared to competing designs with longer development cycles, and by 1957, U.S. Army infantry forces urgently required a modern, magazine-fed infantry rifle to replace the old M-1. In the end the Army chose the conventional T44, which entered production as the M14 rifle in 1957.
In 1957, Fairchild/ArmaLite sold a manufacturing license for the AR-10 to a Dutch arms manufacturer, Artillerie Inrichtingen (A.I.). Firearms historians have separated AR-10 production under the AI license into at least four basic identifiable versions, along with various sporting, carbine and other experimental designs and calibers. The four main variants have been termed the Hollywood model (the first ArmaLite prototypes and initial production), the Sudanese model, the Transitional, and the Portuguese model AR-10. A.I. built the vast majority of these rifles, beginning with the Sudanese model AR-10. The Sudanese version derives its name from its sale to the Government of Sudan, which purchased approximately 2,500 AR-10 rifles. The Sudanese was equipped with a very lightweight, fluted steel barrel fitted with a prong-style flash suppressor and bayonet lug, and weighed only 3.3 kg (7.3 lb) with an empty magazine. Over time, A.I. would engineer additional improvements and changes to the AR-10, including the provision of a heavier barrel with a chrome-lined chamber, a different cocking mechanism, and a simplified gas regulator. All of these models used the same 20-round lightweight aluminum magazine, which was designed by Stoner to be discarded in combat once emptied.
AR-10 production was limited, though Guatemala, Burma, Italy, Cuba, Sudan and Portugal all purchased AR-10 rifles for limited issue to their military forces. Sudanese AR-10s were employed in frequent clashes with guerrilla forces and conflicts with neighboring countries, and a few captured rifles eventually turned up in unofficial service with various African and colonial armies, police, and guerrilla forces. The AR-10 remained in service with Sudanese Special Forces until 1985. In 1958, a special 7.62x39mm caliber variant of the Sudanese AR-10 was produced in very small numbers for evaluation by Finland and Germany. That same year, a 16" barreled AR-10 was developed in response to a request by KLM Airlines for a carbine that could be issued to their crew for transpolar flights as part of an Arctic survival kit, and approximately 30 carbines were eventually produced. A number of Transitional AR-10s were also fitted with a folding bipod designed to lie flat under the forearm. The Italian Navy acquired the AR-10 for its COMSUBIN underwater commando teams. Germany, Austria, the Netherlands, Finland, and South Africa also purchased small numbers of the AR-10 for test purposes, and Cuba's Batista government purchased 100 "Transitional" model rifles in 1958. Fidel Castro's forces eventually captured the AR-10 shipment intact. In 1959, Fidel, his brother Raul, and Che Guevara test-fired the AR-10 outside Havana, and were reportedly impressed by the weapon's firepower. In June 1959 Castro gave the AR-10s to a group of communist revolutionaries from the Dominican Republic who returned there the following month in a seaborne and airborne invasion. Betrayed by local residents, the rebel forces (led by Cuban officers), were surprised at the water's edge; those dropping via parachute were hunted down in the following days by the Dominican army. Captured AR-10 rifles from the Batista shipment were found on the bodies of guerrillas killed in firefights with government forces.
The final Artillerie Inrichtingen design is known as the Portuguese model AR-10. This final version incorporated all that had been learned to date about the AR-10, including infantry service rifle and field test reports. In addition to the heavier barrel, optional bipod, and plastic/metal handguards of the Transitional model, the Portuguese variant had wider bolt lugs, a stronger extractor, a new three-position gas regulator, and a cocking handle featuring a forward bolt assist. It is believed that approximately 4-5,000 Portuguese variants were produced; nearly all of them were sold to the Portuguese National Defense Ministry by the Brussels-based arms dealer SIDEM International in 1960. The AR-10 was officially adopted by Portuguese Hunter paratroop (Caçadores Pára-quedista) battalions, and the rifle saw considerable combat service in Portugal's counter-insurgency campaigns in Angola and Mozambique. In U.S. Army tests at Aberdeen Proving Ground in November 1960, and later in Portuguese service, the AR-10 gained a reputation for accuracy (some rifles would group into 25 mm (1 inch) at 100 meters with service ammunition); the paratroopers also found them reliable despite rugged service conditions in African jungle and savannah. A few Portuguese and Sudanese model AR-10s found their way by various means to nearby African countries; in Chad, the AR-10 was much appreciated by members of French Foreign Legion. As one police instructor in the Congo stated, "It was a good combat weapon that never failed me; a bit too long (but not as bad as the FAL or M-14) for house-to-house work or really heavy brush, but great for 400-800 meters, in the flats - and really nice on the body, after wandering around 12-14 hours looking for bad guys."
Some Portuguese-model AR-10s were fitted with A.I.-modified upper receivers in order to mount 3x or 3.6x telescopic sights. These rifles were used by marksmen accompanying small patrols to eliminate individual enemy at extended ranges in open country. Other AR-10s were used by the paratroopers in a secondary role to launch rifle grenades. The AR-10's built-in gas cutoff design enabled it to fire Energa rifle grenades without adjustment of the gas system, and the self-loading action would even eject the spent blank shells and load the next one, allowing several grenades to be quickly fired. The added recoil took its toll on rifle stocks, and some Portuguese rifles were retrofitted with all-metal buttstocks to better withstand the added recoil and strain caused by firing the heavy grenades. Plans to order additional quantities of the AR-10 rifle were stymied after Holland embargoed further shipments of the rifle to Portugal; paratroopers deploying to Africa in later years were subsequently issued a collapsible stock version of the German Heckler & Koch G3 rifle. Nevertheless, the AR-10 continued in service with a few Portuguese airborne units, and was in use as late as 1975 in the Portuguese Timor (East Timor) decolonization emergency.
By 1960, hampered by Dutch export restrictions and discouraged by the lack of arms sales to major national purchasers, Artillerie Inrichtingen decided to exit the small arms production business altogether, and ceased all production of the AR-10 under its license from Fairchild-ArmaLite. By that time, less than 10,000 AR-10s had been produced, mostly military select-fire rifles, with a few semi-automatic only rifles produced for civilian use.
In later years, some ex-military Sudanese and Portuguese model AR-10s were sold to civilian markets in the U.S., Canada, Australia, and New Zealand. Nearly all of the rifles imported to the latter three countries had their full-automatic fire selector disabled. As many as 2,500 Australian AR-10 rifles may have been seized and destroyed as a result of anti-gun legislation in 1997.
Most of the AR-10 ex-military rifles shipped to the USA were in the form of parts kits, having been previously dismantled, though a few were legally imported as National Firearms Act (NFA) weapons. Large numbers of AR-10 7.62 mm magazines were imported as well. Many of these kit rifles were combined with various semi-auto receivers made by civilian manufacturers in order to permit legal ownership
In 1958, ArmaLite developed the 5.56 mm AR-15 from the AR-10. The company continued its efforts to sell both the AR-10 and AR-15 to various military forces around the world. However, the AR-10 rifle marketed by ArmaLite after 1958 was not the product-improved AR-10 developed by Artillerie Inrichtingen, but rather a design scaled-up from AR-15 plans and specifications, the AR-10A. None of the improvements incorporated by Artillerie Inrichtingen over three years of production were used in the new AR-10A. Although the AR-10A did not benefit from the modifications undertaken by the Dutch licensee, it had some differences from the AR-15 (besides caliber and part dimensions), including a different bolt, trigger, and cocking handle design, along with a magazine canted forward at a five-degree angle. While interest in the AR-15 was considerable, the AR-10A failed to attract any orders from domestic or foreign military customers. In 1959, ArmaLite sold its rights to the AR-10/AR-15 to Colt, who successfully marketed the AR-15 to the U.S. military. Disappointed with ArmaLite's marketing efforts, Fairchild dissolved its association with ArmaLite in 1962.
With the rights to the AR-15 design sold and AR-10 production at AI discontinued, ArmaLite next developed a series of new rifle designs in 7.62 mm and 5.56 mm. The 7.62 mm NATO rifle was designated the AR-16. The AR-16 and the other newly-designed ArmaLites utilized a more traditional gas piston design along with stamped and welded steel construction in place of aluminum forgings. The 7.62 mm AR-16 (not to be confused with the M16) was produced only in prototype quantities. By the 1970s, ArmaLite had essentially stopped all new rifle development, and the company became moribund.
 Current ArmaLite AR-10B Rifle Series
In 1995, former Army Ordnance officer Mark Westrom, owner of Eagle Arms, purchased the ArmaLite brand and the company became ArmaLite Inc. Shortly thereafter, ArmaLite introduced a modern version of the AR-10, collectively known as the AR-10B rifle series. The new ArmaLite AR-10B was based on the general design of the AR-15A2, using a forged aluminum receiver with parts scaled up or redesigned as needed to fire the 7.62x51mm NATO (.308 Win) cartridge. The AR-10B prototype was composed of individual sub-components tested on a special lower receiver made of two slabs of aluminum fitted to a Knights Armament Company SR-25 upper receiver assembly, and prototyped using computer analysis. The full prototype AR-10B was the first rifle off the production line. Since 1995, the new ArmaLite company has also incorporated various other design and engineering improvements to the AR-10, including a newly-designed steel magazine derived from the model used on the U.S. M-14 rifle. The current ArmaLite AR-10 is offered in several versions including a A2 and A4 rifle or carbine with collapsible stock, a target model, a 'retro' AR-10B with Sudanese AR-10-style handguard and cocking lever (limited production) and one version chambered in 300 Remington SAUM.
While ArmaLite Inc. holds a US trademark on the name "AR-10", other rifle manufactures currently produce .308 semi-auto rifles that are based on the AR-15/AR-10 design: the DPMS LR-308, KAC SR-25, Rock River Arms LAR-8, American Spirit Arms ASA .308, Fulton Armory Titan, RND Manufacturing's "The Edge" and the German Oberland Arms OA-10.
 Design details
The AR-10 is a lightweight, air-cooled, magazine-fed, select-fire gas-operated rifle that uses the direct impingement gas principle with a rotary bolt locking mechanism. The rifle has a conventional layout; it features an in-line stock, an aluminum alloy receiver and a reinforced fiberglass pistol grip, handguard, and buttstock. While mostly an original design, the AR-10 built upon previously proven concepts. From the FAL it took the hinged receiver system allowing the rifle to be opened for cleaning much like a break-action shotgun. The ejection port cover is similar to that found on the German World War II-era StG44. The bolt locking mechanism is similar to the M1941 Johnson rifle (itself an adaptation of the Browning-designed Remington Model 8 bolt). From the German FG42 and Johnson light machine gun came the idea of straight-line stocks to reduce muzzle climb in fully-automatic fire. The AR-10's method of rotary bolt locking, straight-line recoil, and gas operation enhanced its inherent accuracy.
The gas system, bolt carrier, and bolt-locking design were novel for the time. Most gas-operated rifles divert combustion gases from a port in the barrel to a piston and cylinder arrangement adjacent to the port. In Stoner's design, the gas travels from a port near the middle of the barrel through a steel tube back into the receiver. The gas enters a chamber formed between the rear of the bolt and the inside of the bolt carrier. Once the bolt carrier moves to the rear a small distance, excess gas is vented through holes in its side. This use of the bolt and bolt carrier for the separate actions of a piston and gas cylinder simplified construction and saved weight. Movement of the bolt carrier was in-line with the bore, greatly improving inherent accuracy, as well as keeping the rifle on target as the gun fired. Since the straight-line stock placed the shooter's eye well above the barrel the rifle's sights were mounted high, with the rear sight contained in a carrying handle that also protected the cocking/charging lever.
The receiver is made from forged and machined aluminum to reduce weight. The bolt locks into an extension on the barrel instead of the receiver allowing for a lightweight receiver while not compromising the strength of the bolt locking mechanism. On a few prototype guns, an all-aluminum ("Sullaloy") barrel was fitted at the insistence of George Sullivan – ArmaLite's president – though after the 1957 Springfield Armory tests, all production AR-10s were fitted with standard steel barrels. The stock is made from a plastic-reinforced fiberglass with a core of rigid plastic foam. The handguards and pistol grip are also fiberglass. Fairchild was an aircraft manufacturer, and the use of plastics, titanium, and aluminum were common in the aircraft industry at the time, though not generally used in firearms.
A belt-fed variant of the AR-10 was also offered; the belt was fed by a feed-chute connected to an ammo box carried on the user's back.