Sabotloader...I assume you are talking about deer calibers...As I mentioned in my first post, if a fellow wants a round ball barrel he is best served with deep cut rifling (.015-.018 deep) vs button rifling (.006 deep)...This will better grip the patch...

I could look up the rifling twist on Getz's or Rice's website but as I remember these are standard twists for round ball barrels...

.40 caliber...1-48
.45 and .50 caliber 1-66
.54 caliber 1-72

I know my little .40 shoots good with from 25-70grs of Goex FFF and the .54 does well with from 50-120grs of FFF...That's a pretty wide spread and I vary the charge for game being persued...I believe this is one of the big differences between factory and custom round ball barrels...The factory rifles I have shot had a "sweet" spot where they shot a certain powder charge well...In other words, custom barrels aren't as picky as powder charges and ball/patch combinations...