CMMG Inc Barrel Sub-Assm 16in 6mm ARC Medium Taper Rifle Length 1-7.5 Twist 416SS Salt Bath Nitride Black. Choose between 16 and 20-inch barrel length matte and SBN (salt bath nitride) finish. Specifications for Cmmg Inc Barrel Sub-Assm 16in 6mm ARC: Manufacturer: CMMG Color: Black Caliber: 6mm ARC Barrel Length: 16 in Barrel Profile: Medium Taper Gas System Length: Rifle Length Gas Block Journal Size-Diameter: .750 in Barrel Twist Rate: 1-7.5 Barrel Material: 416R Stainless Steel Gun Model: AR-15 Additional Features: Salt Bath Nitride Condition: New Package Contents: Cmmg Inc Barrel Sub-Assm 16in 6mm ARC What firearm models does the manufacturer say Cmmg Inc Barrel Sub-Assm 16in 6mm ARC is compatible with? The manufacturer says that Cmmg Inc Barrel Sub-Assm 16in 6mm ARC is compatible with AR-15CMMG Inc 60D100C: Barrel Sub-Assm 16in 6mm ARC Medium Taper Rifle Length 1-7.5 Twist 416SS Salt Bath Nitride Black