^^^ What he said. I've got some of these (two for my 550 and one or two for my new 750 that I haven't gotten set up and running yet). Just be sure to record your micrometer settings in your load data record book for each load. Also, their
Calibration Curve Spreadsheets are very handy for developing and keeping data for the various powders that you use, and they work with any micrometer style charge adjustment system (Redding, RCBS, etc.).
