Overview Product Description Ar-15 20in 5.56 A2 Barrel Group 1-7 Rifle GasCartridge : AKK_5.56 x 45Contour : GovernmentFinish : BlackGas System Length : RifleLength : 20''Make : AR-15Make/Model : AR-15Muzzle Threads : 1/2-28Twist : 1-7 Product Videos Custom Field Product Reviews