16” COLD HAMMER FORGED 1 x 7 twist hbar Material Chrome Moly Vanadium per DIN21CrMoV511 (machine gun steel) Chrome lined per 1.2.2.2 of MIL-STD-171 and QQ-C-320, Class 2 (conventional hard or flake chrome) Phosphate per 5.3.1.2 of MIL-STD-171 HP & MP tested 1/2 x 28 tpi threaded and chambered in 5.56mm NATO Stripped Barrel.