The Colt AR15A4 is a semi-automatic rifle chambered in 223 Rem5.56 NATO. The 20 chrome lined barrel is accompanied by a picatinny rail on the receiver. A detachable handle can be mounted there along with a variety of optics. Designed for personal defense and sporting needs the Colt AR15A4 features A2 sights a standard pistol grip and fixed stock.DetailsAction Semi-Auto - Caliber 223 Rem5.56x45 NATO - Capacity 301 - Sights Fixed Front Adjustable Rear - Twist 17 - Barrel Length 20 - Overall Length 39.5 - Weight 7.71 lb - Safety Ambidextrous - Finish Anodized - This Semi-Automatic Colt Rifle is a throwback to the full size AR-15 which gave birth to the Modern Sporting Rifle. The AR15A4 is defined by its 20 17 Twist Government Profile Chrome Lined Barrel and A2 Fixed Buttstock. It also features a flat top upper receiver with a detachable carry handle.