RCBS pioneered the development of 3-Die Sets for straight-wall rifle and pistol cases, simplifying the reloading process. The Carbide Sizer Die sizes the case and de-primes, with a carbide sizer ring that eliminates the need for lubrication. The Expander Die expands the case to the proper diameter, while also imparting a flare or bell at the case mouth to aid in smooth bullet feeding. Finally, the Seater Die seats the bullet and applies a roll crimp, ensuring a secure fit. This set is perfect for those reloading straight-wall cartridges for revolvers and lever guns.