The RCBS 3-Die Roll Crimp Set is designed for use with popular straight-wall pistol cartridges, offering precision and reliability for reloading enthusiasts. This set includes a steel Sizer Die, Expander Die and Roll Crimp Seat Die, each crafted for optimal performance. The Sizer Die requires lubrication to properly size the cases, ensuring a smooth operation. The Expander Die expands the case to the correct diameter, allowing for easy bullet insertion. The Roll Crimp Seat Die not only seats the bullet securely in the cartridge case but also 'roll' crimps the case, preventing any movement during recoil for improved accuracy and reliability. Perfect for reloaders who demand quality and precision in every round.