Many today will contend that a .308 caliber and larger AR is a modification of the AR-15 design, which of a .5.56mm semi-auto direct gas impingement rifle. Well the funny thing is it’s actually the other way around.
Introducing Sullivan and Michault
In the early 1950s, an engineer who moonlighted as an attorney, George Sullivan, teamed up with a talented inventor by the name of Jacques Michault to design a breed of new rifles that could be pitched to militaries around the world. These new guns, products of the latest design techniques, used instead of the WWI/WWII standard wood stocks and steel receivers, would be made with space age plastics and aluminums wherever possible. They would also include such forward thinking designs as built-in carrying handles, hollow pistol grips that could accept a purpose built cleaning and maintenance multi-tool that predated the Leatherman by thirty years, and elaborate flash suppressors.
Sullivan and Michault took their concepts to Dick Boutelle, president of aircraft maker Fairchild Aviation (maker at the time of the C-119 Flying Boxcar and the C-123 Provider transports for the Air Force), and Boutelle saw potential. This spawned Fairchild subsidiary Armalite, founded in 1954. With the new company came a pair of designers and engineers, L. James Sullivan and one Eugene Stoner. The latter soon cranked out the AR-5, a 22 Hornet chambered survival rifle for the Air Force (to come complete in new C-119s and 123s!) and the follow-on .22LR caliber civilian AR-7 “float gun.”
By 1955, this plastic rifle dream team, with the addition of Melvin Johnson, who had a very forward thinking rifle/light machinegun adopted briefly by the Marines in World War II, coughed up the basic design for a revolutionary battle rifle.
Design of the AR-10
With the armies of Free World chasing 7.62x51mm caliber battle rifles (the T44E5 which became the M14 in the U.S. and the FN FAL/CETME/Sig Stg.57 families in Europe), the Johnson-Sullivan-Stoner team at Armalite switched the original 30.06 caliber rifle design they were working on to one that accommodated the new NATO round. This gun was gas operated, using a modified Ljungman-style direct impingement action with a rotating bolt. The ambi charging lever was atop the upper receiver, hidden under an elevated carrying handle, which held the high-line aperture rear sights. All exposed metal surfaces were given a thick anodized/parkerized finish.
Select-fire and capable of being rattled off at a blistering 650-750 rounds per minute, capable of emptying a “disposable” 20-round waffle mag in just two seconds, it was controllable due to a distinctive coke can-sized flash suppressor/compensator and the overall high bore axis of the 21-inch barrel.
So why didn’t it take the world by storm?
Read the rest in my column at Firearms Talk