Armalite AR-180 semi-automatic rifle manufactured in Costa Mesa, California. The AR-180 was developed by Armalite as a simplified, commercially produced version of the AR-18 design and is recognized for its distinctive stamped-steel receiver construction and short-stroke gas-piston operating system. This Costa Mesa-produced example features the characteristic stamped-steel receiver, side-folding stock, adjustable rear sight, protected front sight, and detachable box magazine. The AR-180 utilizes a short-stroke gas piston system with dual recoil springs and guide rods, distinguishing it mechanically from the direct-impingement AR-15. Manufacturer: Armalite Model: AR-180 Manufacturer Location:Costa Mesa, California Caliber: 5.56mm NATO / .223 Remington Action: Semi-automatic, gas-operated Operating System: Short-stroke gas piston Barrel Length:18 inches Overall Length: Approximately 28.75 inches with stock folded / 37.5 inches with stock extended Magazine:Detachable box magazine Stock: Folding Receiver:Stamped steel Sights:Adjustable rear aperture and protected front post The Costa Mesa AR-180 is particularly desirable to collectors because it represents the original American production of the AR-180 before production was later moved overseas. Its distinctive construction and folding-stock configuration make it an important part of the early Armalite rifle lineage.