In 1953 the nations of NATO agreed upon common cartridges like the 7.62x51mm for its rifles so there began a notable increase in guns developed to fill the role of "Battle Rifle" - automatic, self-loading systems chambered to fire full-powered rifle-caliber cartridges. Prolific American arms designer Eugene Stoner worked on what became the ArmaLite "AR-10" during the latter half of the 1950s and, seeing introduction in 1960, the rifle managed to see only modest sales and adoption before falling under the weight of competing types.
On the whole, the design was well-thought out and incorporated a "straight-line" barrel-and-stock arrangement for improved full-automatic fire controllability. Additionally, metallic components were completed in aluminum and critical parts were chromium-lined for long-term reliability. All this worked to produce a lightweight rifle and its action was based on the now-proven AR-15/M16 rifle family. Indeed the M16 is a dimensionally smaller form of the AR-10 and fires the 5.56x45mm NATO cartridge instead. A muzzle compensator had to be fitted to AR-10 rifles due to the muzzle climb inherent in the lightweight design when firing the full-power 7.62x51mm NATO round on full-automatic.
Despite these qualities, the design arrived too late in the marketplace. Prototypes were had as early as 1955 but serial production ended as soon as 1961 with fewer than 10,000 units completed under the Fairchild ArmaLite brand label. Additional examples stemmed from Colt's Manufacturing Company and Artillerie Inrichtingen before the end but legacy production has continued to deliver additional samples to the world.
The AR-10 was also the basis of a series of prototype designs including the AR-10 LMG, a proposed Light Machine Gun form but only serving at the developmental level and nothing more.
The AR-10 series went on to find a home in the inventories (some police, some militay) of Brazil, Burma, Canada, Cuba, Finland, Germany (West Germany), Guatemala, Italy, Nicaragua, Portugal, Romania and Sudan. Conflicts featuring the rifle included the Vietnam War (1955-1975), the Portuguese Colonial War (1961-1974), the Angolan Independence War (1961-1974), the Mozambican War of Independence (1964-1974), the Sudanese Civil War (1955-1972) and the Portuguese Timor Conflict (1975-1976).