i was thinking about a wildcat based off 7 rum necked down to .257 but with the shoulder pushed back and haveing longer neck with a case overall length of about a 30-06. if i were to get a custom die for these dimentions, would a full length sizing die work for this? would it end up crushing the case or would it push the shoulder back like i wanted and just trim the neck to length? would it work with a sharp 35 or 40 degree angle? if not, how would i go about pushing the shoulder back to shorten up the case?