Black powder with jacketed bullets can deliver some surprising accuracy.
My bro's .45 3 1/4" Shiloh Sharps had only .0015" deep rifling - yes 1 1/2 thou, yet with 100gr. 2F GOEX and 300gr. Jacketed Hornady's, he made many 3-shot cloverleaf groups at 100 meters, and 3/4" to 1" 3-shot groups with the same load and 500gr. Hornady RN's. We didn't chronograph these loads for some reason. They were accurate and the next jacketed bullet just pushed out all the fouling from the last shot, with never more than one shot's fouling in the bore.
We drilled nad tapped the top flat to hold a Williams base and mounted a 2 1/2X Bushnell scope for load testing.
Yes = cloverleafs at 100 meters with a 2 1/2X scope.

I had forgotten about 9.3x74 brass being usable as long .410 brass. Good stuff. Years ago, I had planned on rifling the chokes of a .410 SxS shotgun, but I've never had one of those to work with. My buddy would not donate his for this experiment. It would have turned out about like a .40-82 Winchester, but more of a "paradox" instead of fully rifled.