A fwt barrel has a muzzle diameter of .550 so a whelen or 9.3 is getting awfully skinny. It will also be a few ounces lighter than the same rifle as a 30-06, just something to remember. Rebarrelling to a 358 winchester or 284, you might have to have some work done to feed properly. (358 would be better off a 308 fwt I suspect)
Not many talk about it but from personal experience a 35 whelen with heavy bullets recoils noticeably lot more than the same rifle in a 30-06, just something to consider in the equation.
