Redding Neck Sizing Bushings are sold in a wide range of diameters including .256 .261 .262 .288 .307 .309 .311 and others. Regardless of the diameter chosen all of the sizing bushings used for reloading are made of steel that has been heat treated and have a titanium nitride treatment to increase the effective surface hardness. This also helps reduce friction associated with sizing. The bushings are made to cover calibers from .17 to .338 while providing the exact amount of neck tension needed to hold the bullet firmly in place but without causing excessive resizing.