These seaters have a precision fitting bullet seating stem which is spring loaded. As the bullet and case move up into the seater positive alignment is insured. The micrometer adjustment on the seating stem simplifies setting and recording bullet seating depth. The micrometer is calibrated in .001 inch increments, is infinitely adjustable, and has a zero set feature. This seater has no crimping features. Crimping should be done with a separate Redding Profile Crimp or Taper Crimp die. The Competition seating die for the handgun and straight wall cases is compatible with most progressive reloading presses.
Big Book Catalog, Issue:68, Page:535
Sinclair, Issue:5B, Page:042