AR-15 M16 M4 16" 5.56NATO 1:8 Barrel
AR-15 M16 M4 16" 5.56NATO 1:8 Barrel, Chambered in 5.56 NATO 16" length ATF compliant caliber marking on barrel Carbine length gas system 1:8 right-hand twist 4140 chrome-moly lining Hard black nitride coating 0.063" gas port 29.1oz weight