hanshi
Cannon
Tenngun is spot-on about 1-48" twist; it was indeed a rather common twist rate back in the day. I had a DeerHunter for 20 years that grew fat on a diet of prb. The rifling in them isn't a "compromise" twist. The grooves in mine were deep enough for prb to be fast and accurate. I've killed more deer than I can actually ballpark and every one dropped from only one .50 patched ball each. I load rather tight loads and snug loads are going to give you accuracy. With prb the rifling has to be deep enough to give the patch room to compress into the grooves.