3 Die Roll Crimp Set Features RCBS 3 Die Roll Crimp Set for popular straight wall rifle cartridges. The die set features a steel Sizer Die Expander Die and Roll Crimp Seat Die. The cases must be lubricated for use with the steel Sizer Die. The expander Die expands the case to the proper diameter to accept the bullet. The Seat Die seats the bullet in the cartridge case and roll crimps the case to eliminate movement during recoil. 3 Die Roll Crimp Set Specifications Brand: RCBS Model: 3 Die Roll Crimp Set Reloading Caliber: 6mm GT Reloading Die Set: Rifle Type Amount: 3 Includes: Sizer Die Roll Crimp Seat Die Expander Die Green Box