Re: .17 rebarel
Where are you going to get 40-50 grain bullets in .17? Berger has discontinued the 37gr VLD. I don't know of too many people who shot the 37gr Berger who got really good velocity and accuracy. If the bullets were driven fast they usually came apart. If you want a big .17 build one on an improved .223 case, the PPC, or the BR and use a 1/9 twist and shoot the 30gr Golds with a BC of .270 or if you find the discontinued 30gr Berger match boattail.
If you wanted to rebarrel to another caliber ignore me since I thought you were talking .17s.