The revolutionary new Redding Competition Neck Sizing Die with interchangeable bushings (sold separately) brings an advanced level of precision to Competition Shooters. The cartridge case is completely supported and aligned with the sizing bushing before the sizing process begins. As the sizing process starts, the cartridge case remains supported in the tightly chambered, sliding sleeve as it moves upward while the resizing bushing self-centers on the case neck. The decapping rod is maintained in precise alignment by using the internal parts of the die as a linear support much like that of a firing pin. Meanwhile, the micrometer adjustment of the bushing position delivers precise control to the desired amount of neck length to be sized. Although this die was designed for use by Competition Shooters who have meticulously prepared their cartridge cases and do not wish to use a sizing button, carbide size button kits are available separately. The proper bushing size can be easily determined by measuring the outside neck diameter of your loaded cartridges with a precision micrometer. Then, simply subtract .001" from the cartridge that had the smallest average neck diameter. Moly coated bullets may require tighter necks and the use of bushings .001” or .002” smaller.