What Does The AR Stand For?
What Does The AR Stand For? The letters stand for ArmaLite Rifle — and not for “assault rifle” or “automatic rifle.” ArmaLite first developed the AR-15 in the late 1950s as a military rifle, but had limited success in selling it. What caliber is an AR-15 assault rifle? Colt AR-15 Cartridge.223 Remington 5.56×45mm NATO Action