Spikes Tactical Barrel .308 - 20in CHF Alloy 1/12 Twist. 308 barrel you will ever install on your AR-10. It is recommended to be used with the Spike's 308 gas tube. Specifications for Spikes Tactical AR-10 .308 Cold Hammer Forged Barrel: Manufacturer: Spikes Tactical Color: Black Caliber: .308 Winchester Gas System Length: Rifle Length Gas Block Journal Size-Diameter: .750 in Condition: New Projectile Caliber: .308 Caliber Features of Spikes Tactical AR-10 .308 Cold Hammer Forged Barrel: Chrome Lined Cold Hammer Forged 7.62 Nato Chamber M4 Style Ramped Barrel Extension MilSpec Phosphate Coating Heavy Profile Package Contents: Spikes Tactical AR-10 .308 Cold Hammer Forged Barrel Spikes Tactical SBX2005-RL: Barrel .308 - 20in CHF Alloy 1/12 Twist