AR-15 Barrel: 24 Heavy Straight Fluted Barrel with 1:8 Twist Chambered in 5.56/.223 Stainless Finish 416R Barrel is not threaded for Flash Hider has 11° Target Crown Rifle Gas System - Length: 24 - Profile: Heavy - Twist: 1-8 - Finish: Stainless - Material: 416R - Caliber: 5.56/.223 - Flutes: Straight - Gas System: Rifle - Gas Block System: 0.936 - Gas Hole Diameter: 0.093