The AR-18 is a gas-operated 5.56×45mm assault rifle, designed at ArmaLite in California by Arthur Miller, Eugene Stoner, George Sullivan, and Charles Dorchester in 1963. Featuring a lightweight stamped metal lower receiver and a folding stock, it was intended as a lower-cost alternative to the AR-15, which had just been selected by the U.S. military as the M16.
Despite the AR-18 was never adopted as the standard service rifle of any nation, its design is said to have influence on many later weapons such as the American Adaptive Combat Rifle, the British L85, the Japanese howa type 89 and the German G36.