The Lee Auto Prime Hand Priming Tool is a great tool for the hand loader wanting to prime each brass case by hand. The Lee Auto Prime utilizes special shell holders that will only fit the Auto Prime, they will not fit in a reloading press. There are twenty different shell holder sizes to suit the needs of all reloaders. Auto Prime Shell holder utilize the same number as Lee Universal Shell holders and will fit the same cartridges. Specifications: Fits: - .17 Remington - .221 Fireball - .222 Remington - .222 Remington Magnum - .223 Remington - .6x47mm (6mm-223 Remington) - .32 Short Colt - .32 Long Colt - .32 Smith & Wesson - .32 Smith & Wesson Long - .32 Colt New Police - .380 ACP