The Lee Precision Shell Holder #11 fits .44 Spccial, .44 Smith & Wesson Special, .44 Remington Magnum, 10.9x33mmR, .45 Colt, .45 Long Colt, .45LC, .444 Marlin and .454 Casull cases. It is made from hardened steel which has been machined to close tolerance for use with the Lee New Auto Prime, Lee Ergo Prime, Lee Auto Bench Prime and the Frankford Arsenal Hand Priming Tool.