For FMJ bullets mounted in bottle neck cases, roll crimping is generally not ever used unless a cannelure is present on the bullet, to prevent causing bullet deformation when crimping. Rimless, straight wall cases, on the other hand, require a taper crimp, because they headspace on the case mouth; roll crimping causes headspacing problems on these cartridges. Rimmed, belted, or bottleneck cartridges, however, generally can safely be roll crimped when needed. Three dies are normally supplied for straight walled cases, with an optional fourth die for crimping. Crimps for straight wall cases may be taper crimps, suitable for rimless cartridges used in autoloaders, or roll crimps, which are best for rimmed cartridges such as are used in revolvers.
Taper Crimp dies are available in any caliber. Select the caliber you need from the Caliber List for pricing and ordering information.