It's very funny you mention that today... Just yesterday I answered an e-mail from a fellow shooter from Brazil. In that psot I explained to him about the chamber he is using and being able to match a bullet to the chamber and that since he has a longer freebore, a 1-13 or 1-12 twist barrel may work well with 155 Palma's or 168's. He is using a Benchrest gunsmith for his chambering, and and his asperations are to shoot sillouette, where the plates have to not only be hit, but knocked down. The heavier bullet is the key. I suggested instead of his .30 BR, possibly the .30-47 or a .308 would be a better set up. My thoughts would be to go with what ever he can have chambered best and be able to feed best. A lot of his work is done up here and parts have to shipped through an importer etc. Up here I would use the .30-47, we have one and it works well, however our reamer is set up for the short Robinett Bullets. A throating reamer could change that problem.
Paul