Straight out of the RCBS Special Order section, yet listed at a reduced price, the Safari Die Series' 3-Die Roll Crimp Set, 500 Nitro Express 3 inch, covers straight-wall cartridges typically used for dangerous game in Africa. Its steel sizer die sizes the case and de-primes. Note: Cases must be lubricated. The Expander Die expands the case to the proper diameter to accept the bullet, and it imparts case mouth flare/bell for bullet feeding. The Seater Die seats the bullet and roll crimps. Sizer Die sizes and de-primes case Expander Die expands case to proper diameter to accept bullet and imparts case mouth flare/bell for bullet feeding Seater Die seats the bullet and roll crimps Component and Caliber Reference Table