There are other primer seaters on the market, but none quite like our exclusive Forster Co-Ax Primer Seater. Unlike other seaters, ours is designed so the operator can eliminate all slop when working with a specific cartridge. That translates into perfect seating, reliable ignition and reduced misfires. No additional shell holders are required. The E-Z-Just jaws close to securely grip most modern rifle and pistol cases with a rim thickness of .045″ to .072″. Large and small primer tubes have an open slot and primers stack sideways for added safety.