The AR-180 is the semi-automatic variant of the AR-18 assault rifle which was produced by Armalite from 1963-1980. The AR-180 itself is the civilian-market variant of the AR-18 which was the brainchild of Armalite’s Arthur Miller, George Sullivan, and Charles Dorchester and was designed to be mass produced by third world countries using simple low technology production techniques like sheet metal stamping rather than advanced and expensive manufacturing technology like the aircraft aluminum investment casting techniques needed to produce the AR15. The AR18 design played a major role in the design of the British SA80.
The AR-180’s became one of the first military-type semi-automatic rifles to become widely available in the USA due to its cheap production costs. The AR-180 was built to chamber the 5.56x45mm NATO round and had a detachable scope mount, folding stock, and a flash suppressor/muzzle break.