I tried a few years back with a "Sporterized Hawkin Carbine" from Cabelas, I couldn't get anything to group under 4" at 50yrds off bench! Widely scattered,,took the gun back and got in-store credit.
Now I ain't tryin ta be rude,, but a prb out of a 1-28 at 15yrds will get ya one hole (but so will a good round rock!) at 20 they open to 3",, at 50??,,well the twist wasn't made fer round ball,period. It doesn't matter what the charge is,,it just don't work,,shot to shot, load after load,,,
I use too think it did,,because every few shot's one would hit proper,,but every few shot one would miss the paper too. I had ta try it ta learn,,,
luck to ya,,try it yerself