Colt AR15A4 5.56mm: 7 Key Features Buyers Should Know The Colt AR15A4 5.56mm rifle is a classic AR-style semi-automatic rifle built around a 20-inch barrel, fixed A2-style stock, and 5.56x45mm NATO chambering. For buyers who want a traditional full-length AR platform rather than a shorter carbine, the AR15A4 remains a recognizable option. This guide explains […]