The AR-15 is based on the 7.62 mm AR-10, designed by Eugene Stoner, Robert Fremont, and L. James Sullivan of the Fairchild ArmaLite corporation. The AR-15 was developed as a lighter, 5.56 mm version of the AR-10. The “AR” in AR-15 comes from the ArmaLite name and stands for “ArmaLite Rifle”. ArmaLite’s AR-1, AR-5, and some subsequent models were bolt action rifles, the AR-7 a semi-automatic rifle and there are shotguns and pistols whose model numbers include the “AR” prefix.
Aero Precision: AC-15M