RCBS 3-Die Carbide Taper Crimp Die Sets are precision-made using proprietary steel. Each set includes a Carbide Sizing Die, Expander Die, and Bullet Seating Die for superior hand-loading performance. RCBS pioneered and developed 3-Die Sets for straight-wall rifles and pistol cases. These sets for straight wall pistol cases build off of that legacy. Each set features a Carbide Sizing die that requires no case lube to speed up your sizing. The Expander die expands the case to the proper diameter to accept the bullet and also imparts case mouth flare/bell for easy bullet feeding. The bullet seating die then seats the bullet and puts on the appropriate crimp for the round being loaded.