CMMG Barrel Sub-Assm 16.1inch MT 4140CM SBN 5.56mm

Perfect for building your custom AR15 upper group. Comes with properly installed M4 barrel extension. All barrel sub-assemblies are properly headspaced. 16.1? Medium Taper Profile 4140 Chrome Moly Salt Bath Nitride Finish inside and out 1:7 Twist 5.56x45 NATO Chamber Threaded 1/2-28 Midlength gas port .750? Gas Journal