Bsf Barrels AR-15 Barrel Features The Bsf Barrels AR-15 Barrel begins as a turned-down 416R stainless steel match barrel before being jacketed in a roll-wrapped carbon fiber sleeve loaded under tension. This approach is used instead of wrapping the barrel directly in carbon fiber a method that has been shown to trap heat and lead to delamination over time. The carbon fiber sleeve is engineered to expand at the same rate as the 416R stainless steel beneath it keeping the two materials moving together as the barrel heats during firing. Machined slots in the carbon fiber let air circulate around the barrel venting heat faster without introducing any risk of the wrap separating from the steel underneath. Because the barrel stays under tension from the carbon fiber wrap the rifling remains straighter as the barrel warms helping preserve accuracy through a longer string of fire than an unwrapped steel barrel of similar weight could manage. This construction delivers superior stiffness and strength while keeping the barrel extremely lightweight a valuable trait on a short 12 inch barrel where weight and balance matter even more. Button rifled with 6 grooves and a 1:8 inch twist rate suited to heavier .338 ARC projectiles the barrel is threaded 5/8x24 for muzzle device or suppressor mounting. For AR-15 platform builders working with .338 ARC in a compact configuration this carbon fiber wrapped barrel offers a lightweight heat-resistant option for sale at GrabAGun. BSF Barrels AR-15 Barrel Specifications Manufacturer: BSF Barrels Model: AR-15 Barrel Caliber: .338 ARC Gun Platform: AR Style Barrel Length: 12 Barrel Finish: Carbon Fiber Barrel Material: Stainless Steel Barrel Description: Button Rifled Twist Rate: 1:8 Diameter: .875 Grooves: 6 Thread Pattern: 5/8x24 Available At: GrabAGun