In 1966 I was trained with the M-14. I was taught

[OneTenthofOnePercent]

69. Armalite developed the AR10 in '57

Armalite's model numbers are sequential. "AR" stands for Armalite Rifle, not 'assault rifle' and there are a number of non-semiauto rifles with the AR-# designations (AR-7, AR-24, etc). They developed the AR10 (1956) as a .308 gas rotating bolt semiautomatic rifle. When the Army requested trials for a smaller intermediate caliber weapon instead, the design was simply scaled down and named the AR15 (1957). The difference between the AR10 and AR15 is similar to the difference of the long and short actions seen in the Remington 700 bolt rifles.

Colt Purchased the rights to the AR0 and AR15 in 1959. Colt continued to produce rifles with the AR15 nomenclature in addition to the CAR-15 models. Subsequently, the AR15 ws adopted by the military with select fire capabilities and designated the M16. The trademark "AR15" or "AR-15" remains registered to Colt Industries, although ther AR-15 manufacturers make "AR-15 clones" marketed under separate designations, although colloquially these are sometimes referred to by the term AR-15.