5.56 16" Barrel 1:7 GP Mid Length Gas System Nitromet
5.56 16" Barrel 1:7 GP Mid Length Gas System Nitromet, 5.56 NATO 16" GP 1:7 Mid Length RH 4150 CrMoV, Nitride barrel, has been treated with Nitromet(TM) (salt bath nitrocarburized) inside and out with a hardened finish that results in a bore life 40% greater than with traditional chrome-lining without affecting accuracy. Barrels are made of 4150 Chrome Moly Vanadium steel, chambered for 5.56mm NATO, button rifled with 1-7 twist rifling, and machined to a standard M4 profile. Gas port drilled for a carbine length gas system, .750 diameter at the