The long range accuracy of your black powder cartridge loads depends on the consistent ignition and uniform combustion of the black powder from cartridge to cartridge. Using a drop tube to charge your cases and compressing the powder charge are two ways to increase uniformity. It is also the only way to actually get 70 gr. of black powder into a 45-70 case. Our compression plug screws into the bottom of the micrometer top of your EASY SEATER die in place of the bullet seating stem. Do not remove the cartridge guide sleeve. Screw the micrometer top down until the proper amount of compression is achieved (See instructions included with the plug.) and record the micrometer reading so you can return to the same setting at your next reloading session. Need to seat a shorter bullet or change the seating depth? No problem. The micrometer makes it easy to dial in the change you need. Available in 38, 40 and 45 cal. only. PRICE $15.00 PLUS SHIPPING