Proof Research Barrel Bolt 264 27 inch 8 Twist 4 Groove Stainless Steel M24. These Rifle Barrels from the innovators at Proof Research are lightweight and ergonomic and won't weigh you down at the range. With extreme pressure resistance the Carbon Fiber 28 inch Bolt-Action Barrel combines strength with toughness to withstand repeated usage. Erosion wear and weather resistant this aftermarket accessory is great for professionals and beginners alike. Take your aim to the next level with a Proof Research Bolt Action Barrel. Specifications for Proof Research Bolt Action Barrel: Manufacturer: Proof Research Color: Silver Barrel Length: 28 in Barrel Material: Stainless Steel Threads per Inch: Non Threaded Barrel Shank Diameter: 1.2 in Features of Proof Research Bolt Action Barrel: Available in a variety of calibers Precision machined Traditional Steel Design Package Contents: Proof Research Bolt-Action Barrel Proof Research 101094: Barrel Bolt 264 27 inch 8 Twist 4 Groove Stainless Steel M24