Many shooters are finding an increase in accuracy and clean burning characteristics by compressing their Black Powder Cartridge loads .200"-400". Made to screw in place of your expander plug on Lyman, RCBS, 4-D and Redding dies. These have a lock ring set up same as the custom expanders so you can remove them without losing your setting. .32 rifle, .38 rifle, .40 rifle, 43 Spanish, .44 rifle, .45 Colt, .45 rifle, .50 rifle other sizes available by special order. We also sell the die bodies separately. Please specify make of dies if you are purchasing a compression plug only.