The ARX-160 is composed of two receivers, both manufactured mostly in polymer, and operates through a short-stroke piston system. Feeding is through STANAG magazines. The weapon's unique features include ambidextrous safeties, magazine catches and charging handle, the ability to change which side spent casings are ejected, a quick-change barrel which can be removed and replaced in seconds without tools, picatinny rails and a foldable telescopic stock.