I recently acquired a .58 cal barrel with the following specs.
.580 bore
.012 groove depth
8 wide grooves/narrow lands-similar to Forsythe
1/70 twist.
Ordinarily my load recipe would include a .570 ball and .018 patch, at least for starters, but I'm thinking the very narrow lands/wide grooves, .012 depth may
require a bigger ball(.575?) and/or a thicker patch.
Comments will be appreciated.
Duane