Redding Competition Seating Dies delivers the precision and accuracy preferred by the most discriminating handloaders. Now you can easily convert your conventional seating die to a precision micrometer seating die for use with STD (standard) bullets for precise, repeatable bullet seating depths to within 1/1000th of an inch and potential world-record accuracy. Designed for all seating dies that use a seat plug with 1/2-20 threads. Easily changes from one die to another, just match the number on your current seating plug to the corresponding bullet seating micrometer number.