The RCBS Competition Dies are for the competitive marksman that measures success in fractions of an inch.
The Competition Seater Die has a micrometer adjustable, free floating and self-centering bullet seating system with convenient bullet loading window. Bullet seating depths are adjustable to .001". Dies have a durable black oxide finish. Not for use with progressive reloading presses. A shellholder is not included and must be purchased separately.
Big Book Catalog, Issue:68, Page:533
Sinclair, Issue:5B, Page:054