Bill,
I use pp in my BC with blackpowder, but have a few loaded to try with smokeless. what dia are these before patching and what are you patching them with? I use 1:30 for mine that are patched to just under bore dia. with the BP, I used a thicker patch to go past bore dia. with the smokeless ones but still haven't made it to a range to see how they do. All I had on hand was H4895 when I loaded mine up. The only load data I had was for a trapdoor using a 485 cast, mine weigh 490 so I figured it was close. I used 40gr of H4895. But check your load books and see what you can find for the others.
Greg