Mebbe it's just me, but, other than the novelty, why would anybody want, WANT, to shoot cartidges in these revolvers?
They ARE BP C&B, powder, ball, cap, grease, or grease then cap, 'less you do both ends.
I don't know, if you wanna shoot cartridge, there are bunches of them guns available. .22 to .50 cal, and everything in between. You wanna make a cartridge shooter, for a project, one thing, but seems like when someone spends 2- 3 hundred bucks for a "conversion" cylinder, all he wants is to justify the expense with cartridge loads. No longer a C&B shooter. Should buy a Glock.
Hey, you can shoot .357 Mag and .44 Mag with BP. If you wanna shoot BP guns with smokeless, have a ball. Just don't ask me to join you. (I know you wouldn't anyhow, but you DO get my point, don't you?)
Cheers,
George