These 6.5 Grendel ''''Type 2'''' chambered barrels are machined from 416R Stainless Steel with a bead blasted finish. Premium Series Barrels feature a Nickel Boron Coated Extended M4 Feed Ramp Extension.Hanson Series Barrels feature Ballistic Advantage's proprietary BA Hanson profile and include a pinned lo-pro gas block. Hanson barrels are not designed to work with aftermarket piston kits.BA Fluted barrels deliver the perfect balance of weight and rigidity. Utilizing six and eight flute designs Ballistic Advantage achieved weight reduction up to and exceeding 16 ounces. Confidently lighten your kit without sacrificing an ounce of accuracy. Mfg: Ballistic Advantage