I recently brought home a 54 caliber full-stock - 27" barrel, seven-groove rifling. When I get the time I'll post pictures and hope that someone can enlighten me as to its likely origin..
In the meantime, I'm wondering what, if anything, is going to shoot well in that bore and rifling? Patched round ball, minnie???? Instead of being square cut, the grooves appear at the muzzle to be rounded.
If I did the old turns of a patched-ramrod trick correctly, the twist rate is something on the order of 1:96.
The very well maintained condition of bore, drum and nipple (musket) suggest to me that a previous owner was a serious shooter. Of what, I don't have a clue.