Sterling AR-180 5.56 NATO Semi-Auto Rifle Sterling-manufactured AR-180 chambered in 5.56 NATO. Produced in England, the Sterling AR-180 is a later-production variant of Eugene Stoner's AR-18 design and is well known for its distinctive stamped-steel receiver, short-stroke gas-piston operating system, and folding stock. Overall, the rifle is in very good condition with signs of handling and use throughout consistent with its age. The Sterling-produced AR-180 rifles are increasingly collectible and make an excellent addition for collectors of Cold War-era military-style firearms and early modern sporting rifle designs.