He’d been in that position for just a year, but ArmaLite had already given the Air Force a new lightweight survival rifle, the MA-1. Stoner paid attention to that design, crafted with “the latest technical advances in plastics and alloys”—a mantra from Lockheed Corporation patent counsel George Sullivan. Stoner’s AR-10 rifle featured an aluminum receiver and plastic stock components, which kept the rifle’s weight down to 7 pounds. The bolt locked into a barrel extension. Though functional, the 7.62x51mm AR-10 had flaws, and ArmaLite had come late to the competition. Encouraged by General W.G. Wyman, Stoner followed in 1957 with an AR-15, a scaled-down rifle firing a 5.56mm cartridge. Its direct-impingement system siphoned gas in a block under the front sight to run the bolt.
Alas, the Army decided the 5.56mm NATO cartridge wasn’t suitable for battle. Hard-pressed to recoup the $1.45 million it had spent in developing the AR-15, Fairchild looked for a buyer. In 1959, Colt bought rights to both rifles for $75,000, plus a 4.5-percent royalty on future sales. Colt couldn’t persuade the Army to give the AR-15 another look, but the Air Force ordered 8,500. When the Department of Defense put the M14 out to pasture in 1963, Secretary Robert McNamara bought 85,000 Colt AR-15s.
The need for infantry rifles rose when the U.S. began fighting in Vietnam. As the M16, ArmaLite’s 5.56mm rifle got refinements, including a bolt assist and sharper 1-in-7-inch rifling to stabilize long bullets. The rifle continues to evolve. Oddly enough, Colt still owns the AR-15 trademark. ArmaLite, now on its own, has registered the AR-10 name, and trademarked the AR-30, AR-50 and M-15.