The PRO barrel line features extremely tight tolerances and are manufactured with pre-hardened chromium stainless steel (416R) that was originally designed for use in Match Grade rifle barrels. This material provides high tensile strength and toughness to withstand typical chamber pressures while still being highly corrosion resistant. This barrel is a match grade drop in bronze finished barrel, is SAAMI spec, and is rifled with a 1:10" twist rate.