If you compare the case dimensions of both you'll find the 9.3x62 is .055 shorter in overall length. The critical dimensions; base to shoulder, shoulder diameter and diameter at the web, are all greater in the 9.3x62 than they are in the 30-06. Hence the 9.3x62 reamer will clean up the chamber and the rebore itself will clean up the throat so that it can be correctly throated for the shorter neck.
