Collet #5 for Classic Case Trimmer.
Step dimensions = .584″ & .675″
Fits:
7.62x54mm Rimmed Russian, 275 Magnum Flanged, 303 Magnum, 375 H&H Flanged, 378 Weatherby, 40-90 Sharps Straight, 416 Rigby, 475 Nitro Express, 9.5x47R.
For unlisted calibers use the cartridge head diameter to select the appropriate collet .