Finegunmaker,
Lother Walther makes the best barrels I have used to date and they make a 9.3 barrel with a 1x14 twist and that is the best for 250 to 320 gr. bullets....

A Mauser or M-70 can be opened in the rear and require less than a hundred thousands removal of the front feed ramp, not thats not going to hurt a thing, and you can remove that much metal with your fingernail

But I have to keep in mind that I travel a lot and cannot have a improperly marked case that does not coincide with the caliber of my rifle..I just prefer to not deal with problems like that, be they real or rumored...