Though ubiquitous today, the Armalite's lightweight rifle could easily have failed. In 1957, the company had rushed a prototype of an earlier, larger gun to the US Army, in hope of securing a major contract.During a torture-test at Springfield Armory, the barrel on this experimental AR-10 broke open. Already lobbying hard for their own design, the M-14, the Army's weaponeers cited the AR-10 incident to help quickly dismiss the rival gun as a viable alternative.The California gun-manufacturer, then still a division of the Fairchild Engine and Airplane Corporation, went back to the drawing board. Legendary gun-designer Eugene Stoner and his team scaled-down the rifle.The new AR-15 was a marvel of then state-of-the-art manufacturing processes and materials. Armalite made the AR-10s and -15s from lightweight aluminum and fiberglass, a break from the wood-and-steel guns of the recent past.The AR-15 weighs less than eight pounds with a fully loaded 30 round magazine. By comparison, through World War II and Korea, American soldiers lugged the nine-and-a-half-pound M-1 rifle, which held only eight rounds.
With Armalite's patents long-expired, any company can make AR-15 clones—and they do.
By exploiting his personal connections, Colt representative Robert Macdonald did manage to grab the interest of the US Air Force by showing off the AR-15 to Gen. Curtis LeMay at a birthday party for Fairchild's ex-president Richard Boutelle in July 1960.Macdonald sold LeMay on the guns by letting the cigar-chewing officer blast watermelons in Boutelle's backyard. Then in charge of the flying branch's nuclear bombers, LeMay pushed for the Air Force to buy the rifles for the airmen guarding his planes.
It's not entirely clear if anyone at the time thought the AR-15 would sell well on the civilian market.