I will soon be doing a 30 Major. Question is, to go from 6.5 Grendel brass to .30 cal. Pma has a 6 to 30 neck up mandrel. 21 century has a 6 to 7mm, 7 to 30 cal. So it would require 2 steps. Is that to relax the brass some how so the necks don’t split or is it ok to do it one step which I prefer.