What I mean by lack of correct brass is I understand Hornady uses 30-06 brass, basically, that has a larger rim than what the original size of the brass for the 9.3 should be. The Nosler manual shows rim size for the 06 at .473 and the 9.3 at .470 with the body of the 9.3 case being slightly larger than the 06.
Assuming that everything you wrote above is correct (and your dimensions are, but I don't know about current Hornady brass), I think an important point is being missed:
Regardless of whether a rifle is born as a factory 9.3x62, or a 30-06 that is
rebarreled to 9.3x62, or a 30-06 that is
rebored to a 9.3x62, they are all going to have the same 9.3x63 chamber, unless something "incorrect" gets done in one of the second two processes.
The 9.3 reamer, as you point out, completely "cleans up" the 30-06 chamber when a rebore is done.
The .003 difference in rim diameter is meaningless.
So, the point of the OP is based on fallacy, if I am understanding the OP question (which maybe I'm not).
Cheers,
Rex
