CMMG MK3 .308 Winchester Threaded AR Barrel 20in Medium Taper Rifle Length 1-10 5/8x24 Black. Comes with a properly installed M4 barrel extension. All barrel sub-assemblies are properly headspaced. Comes with the CMMG Lifetime Quality Guarantee. Specifications for CMMG MK3 .308 Winchester Threaded AR Barrel: Manufacturer: CMMG Color: Black Caliber: .308 Winchester Barrel Length: 20 in Barrel Profile: Medium Taper Barrel Twist Rate: 1-10 Gun Make: CMMG Gun Model: CMMG Mk3 Weight: 2.4 lb Gun Type: Rifle Package Contents: CMMG MK3 .308 Winchester Threaded AR Barrel M4 barrel extension What firearm models does the manufacturer say CMMG MK3 .308 Winchester Threaded AR Barrel is compatible with? The manufacturer says that CMMG MK3 .308 Winchester Threaded AR Barrel is compatible with CMMG Mk3CMMG 38D2C0C: MK3 .308 Winchester Threaded AR Barrel 20in Medium Taper Rifle Length 1-10 5/8x24 Black