Thats what I was thinking was rebore,but isn't that the same as rechambering?
Rechambering is just that... Running a reamer in the chamber and changeing it to a bigger cartridge...
Reboreing is "boreing" the hole in the bbl out to a bigger size, and re-rifleing it to a bigger caliber...
Caliber is REALLY about the diameter of the bullet, and the CARTRIDGE is really is about what case that holds the powder is used to drive that bullet.
Your origional question asked about going from a .308 Win. to a .338 Federal. (.308" to .338") What is needed to do that is, to to bore out the 308 to 338... Then run a neck reamer in the chamber to get the bigger neck of the Federal...
DM