I have bored barrels to 338-06 and 35 Whelen before and the muzzle is getting real thin. I would imagine that a 9.3 by 62 and 8 by 57 would have to start with a new barrel blanks, as the cases are shorter than the 30-06. Those original barrels cannot be set back because of the gas system.
That was my first thought reading this so I just measured the muzzle on my Garand. It's 0.510" so a 0.366" bore will leave you with 072" wall thickness which I understand to be too thin for a rebore. Don't the guys doing the rebores want 0.100" to 0.125" minimum wall thickness?
