RF-85 Treated Non-treated Barrel Length 16 inch Barrel Material 4150 Chrome Moly Vanadium Barrel Contour Standard Fluting None Twist Rate 1:10 Federal Firearm License Required for Purchase No Gas System Length Mid Length Gas Block Diameter .750 inch Thread Pattern 5/8 - 24 Weight 2.000000 Muzzle Device Not Included Unit of Measure EA Product UPC 640901515731 Lead time 30 Country of Manufacture United States