FULL LENGTH SIZING DIES These dies size the ""full length"" of your cartridge from the neck down to the base of the case. Includes a decapping assembly and expander ball. Available individually or in Full Length Die Sets and Deluxe Die Sets. We recommend the use of a headspace gauge when setting up a full length sizing die. SMALL BASE FULL LENGTH DIES: These dies are designed for firearms with custom chamberings that are tighter than SAAMI specifications. We use them on our gas guns with close tolerance chambers as well.