CMMG Inc Barrel Sub-Assembly Medium Taper 300 BLK 16.1in 4140CM Salt Bath Nitride. Comes with properly installed M4 barrel extension. All barrel sub-assemblies are properly headspaced. Features of CMMG Inc 16inch 300 Acc Blkout 1:7 Carb Gas: 16.1" Multi Role Profile 4140 Chrome Moly Salt Bath Nitride Finish inside and out 1:7 Twist 300 AAC Blackout Chamber Threaded 5/8-24 .750" Gas Journal Specifications for CMMG Inc .300 AAC Blackout Barrel Sub-Assembly: Manufacturer: CMMG Color: Black Finish: Salt Bath Nitride Caliber: .300 AAC Blackout Threads per Inch: 5/8x24 Gun Model: AR-15 Package Contents: CMMG Inc .300 AAC Blackout Barrel Sub-Assembly The CMMG Inc 16inch 300 Acc Blkout 1:7 Carb Gas is a quality addition to the CMMG lineup. For more great deals on AR15 Barrels by CMMG please browse our CMMG Inc Gun Parts page. What firearm models does the manufacturer say CMMG Inc .300 AAC Blackout Barrel Sub-Assembly is compatible with? The manufacturer says that CMMG Inc .300 AAC Blackout Barrel Sub-Assembly is compatible with AR-15CMMG Inc MK4 MT 4140CM .300 AAC Blackout 16.1 Inch Barrel Medium Taper Profile 5/8-24 TPI Salt Bath Nitride Finish