After a case has been loaded a few times, it will stretch beyond maximum length and must be trimmed. Thie Cutter and Lock Stud works for all calibers. You will need only one. The Case Length Gauge (Pilot) and Shell Holder must be ordered as Case Length Gauge and Shell Holder for each caliber. Trim cases by hand or use with an electric drill to trim, chamfer and polish cases faster. Eliminates danger of long cases. Squares the mouth for more accurate bullet seating and exit.