Lee 45 ACP, 45 Auto Rim, 45 Winchester Mag and 45 GAP Carbide Factory Crimp Die sizes the cartridge while being crimped so every round will positively chamber freely with factory like dependability. This die applies a taper crimp. The adjusting screw quickly and easily sets the desired amount of crimp. Trim Length is not critical so this extra operation takes less time than it would if cases were trimmed and chamfered. A firm crimp is essential for dependable and accurate ammunition, as it eliminates the problems of poor ignition of slow burning magnum powders. Features: Carbide ring in base resizes any portion of case that exceeds factory new dimensions Floating crimp ring is finger adjustable to provide the perfect crimp