AR-10
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Design
While mostly original, the AR-10 built upon previously proven designs. From the FAL it took the hinged receiver system allowing the rifle to be opened for cleaning much like a break-action shotgun. The bolt locking mechanism is borrowed from the Johnson M1941 Rifle (itself an adaptation of the Browning designed Remington model 8 bolt). From the German FG42 and Johnson Light Machinegun came straight-line recoil and high-mounted sights. The use of plastics, titanium, and aluminum were common in the aircraft industry at the time though not generally used in firearms.The gas system was quite innovative. Most gas-operated rifles divert combustion gas 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. This utilization of the bolt and bolt carrier for the separate actions of a piston and gas cylinder simplified construction and saved weight. Additionally, 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. However, the straight-line stock placed the shooter's eye well above the barrel, requiring high mounting of the rifle sights. The rear sight was incorporated into a carrying handle. The charging lever was mounted within this handle in the form of an upside-down "trigger."
The receiver was made from forged and machined aluminum to reduce weight. The bolt locked into an extension on the barrel instead of the receiver allowing for a lightweight receiver while not sacraficing strength in the bolt locking mechanism. On a few prototype guns, the barrel was made of a stainless steel liner swaged inside an aluminium barrel, though this was soon abandoned as impractical. The stock was made from a plastic-reinforced fiberglass with a core of rigid plastic foam. The handguards and pistol grip were also fiberglass. At the time, the AR-10 was the most accurate standard-issue selective-fire military rifle ever built.
History
ArmaLite first opened as a division of Fairchild in 1954, specifically to bring new materials and designs to the firearm industry. They quickly released a number of interesting designs. Later that year they were joined by Eugene Stoner, who started looking for new projects.At the time the 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 FN FAL as the T48. Armalite entered competition late and started work on what would become the AR-10.
The differences between AR-10 and other rifles of the time were stark, and its appearance was unique. When it was introduced in 1955, it was almost two pounds (1 kg) lighter, significantly easier to control in automatic fire, was more accurate in semi-auto fire, and arguably handled better than any other weapon of the period. However, its composite barrel, a untried prototype design installed for the tests over Stoner's objections, burst in a torture test conducted by the United States Army. Armalite replaced it with a conventional chromium-molybdenum-vanadium steel alloy, but the Army rejected the design. Army politics are credited with rejection of both the AR-10 and T48 (FN FAL), along with the fact that the AR-10 at that time was still a brand-new rifle still in development. To many evaluators, it was evident that both of these designs were superior, but they suffered from not having been developed by the Springfield Armory. In the end the Army chose the conventional T44, which entered production as the M14 rifle in 1957.
In 1957, a manufacturing license was sold to a Dutch company named Artillerie Inrichtingen (AI). (AI) made several design improvements to the AR-10 during production, building at least three identifiable versions of the basic military rifle, along with experimental carbine and semi-automatic designs. Production was limited, though Guatemala, Burma, Italy, Cuba, Sudan and Portugal all purchased AR-10 rifles for limited issue to their military forces. Germany, Austria, Holland, Finland, and South Africa also purchased small numbers of the rifles for test purposes. The Portuguese rifles in particular saw considerable combat service in counterinsurgency warfare in Africa with paratroop and other elite forces, where the AR-10 soon gained a reputation for accuracy and reliability despite rugged service conditions.
Production of the AR-10 ceased during the early or mid-1960s with only around six thousand military AR-10's being made, with an additional number in semi-automatic mode for civilian use. In later years, some decommissioned military AR-10s were dismantled and sold as parts kits, and many were combined with various civilian semi-auto receivers in order to permit legal ownership.
With their AR-15 design sold and AR-10 licensed, Armalite next developed "low cost" rifle designs in 5.56 mm and 7.62 mm. These rifles utilized more traditional gas pistons 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. The AR-18 was produced in limited quantites and its basic operating mechanism was later adapted and used in bullpup form as the British SA80. By the 1970s, Armalite had essentially stopped all new rifle development, and the company became moribund.
Rebirth
In 1994, former Army Ordnance officer Mark Westrom purchased an AR-15 manufacturer named Eagle Arms. Eagle purchased the ArmaLite brand name in 1995. Shortly thereafter, they introduced a modern version of the AR-10. The new Armalite company chose to pattern the new AR-10 after the AR-15A2, scaled up to take the 7.62 x 51 mm Nato cartridge, along with various design improvements designed to strengthen the rifle. Ironically, the AR-15 itself was a scaled down AR-10. The new AR-10 is offered in several versions including a carbine and target model. One version is chambered in 300 Rem SAUM.
External links
Books
Pikula, Sam (Major), The Armalite AR-10, 1998
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