Originally Posted by billt
What does the "15" stand for?
The 15th design by ArmaLite.
The AR1 was a bolt action sniper rifle.
AR5 was a .22lr Boltaction take down
AR7 was a semiauto version of the AR5
AR10 is the 308 version of the AR15
AR16 is a gas piston rifle as is the AR18 and AR180 and AR180B (this is where the # doesnt match up.) Read my link a couple posts up, Post #9
The AR17 is a semiuto shotgun...