I worked in a shop for quite a while, and the resident gunsmith specialized in converting .30-06's to .308 Norma or .300 Winchester, .270's to .270 Weatherby, etc. The real challenge was getting the feeding to work properly. His real money maker was correcting that, when not so handy gunsmiths dropped the ball.

Experience is what you get,
When you don't get what you want ;-0