Can i take this Remington 673 Guide Rifle.308win to a gunsmith & have it modified into a 338 Win or .340 weatherby & if so price if you have any idea, what it might cost me to do this...

All your thoughts would be greatly appreciated.

Only reason i want to modify gun is for Elk or moose hunting, i believe .308 caliber is to small, & dealer is marking several hundred dollars off the cost of this Model because I think remington , wont be making it much linger.