that was my thinking. what difference does it make when its contoured? if i got the process right from reading over the years, all blanks are drilled and rifled as is ( uncontoured bull blanks) and the lapped if they do that then threaded contoured and chambered. so if a barrel was recontoured likei said before i would think u would have to chop of some of the muzzle end due to mounting on a lathe and set back the chamber end for the same reason but both would help in the long run by cleaning up the muzzle and throat and could possibly extend the life of the barrel, although most normal shooters wont ever wear one out.

my biggest concern would be running out of threads at the shank in order to properly headspace.

brian