.307 Winchester 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 aligment by using the internal parts of the die as a linear support much like that of a firing pin. The micrometer adjustment delivers precise control of the desired amount of neck length to be sized. This die was designed for use by Competition Shoorters who have meticulously prepared their cartridge cases and do not whish to use a sizing button. Bushings available separately.