AR-15 A4 in 5.56mm NATO, Colt part number AR15A4 The Colt AR15A4 AR-15 A4 Rifle 5.56mm 20in 30rd Black Colt CLT CARBINE AR15A4 20B 223 30R Model: Carbine|AR15 Caliber: 223 Action: Semi-Automatic Capacity: 30+1 Finish: Matte Black Sights: FT: Adjustable Post RR: Adjustable A2 Barrel: 20" Features: Removeable Carry Handle