The Gold Medal Match Series comprises the finest reloading dies built by RCBS®. The Neck Bushing Sizer Die resizes only the case neck, and its changeable diameter neck bushing design has been trusted by benchrest and long-range precision shooters for years. It lets reloaders precisely set the amount of tension on the bullet, reducing work-hardening of the case neck brass, prolonging case life and increasing accuracy. However, getting these benefits requires the use of high-end brass with consistent neck thicknesses. Neck bushings (sold separately) are available in .001-inch increments from .189-inch to .365-inch. Note: Neck Bushings are not included.