Anybody shooting sillhoettes with traditional muzzleloaders using iron sites and PRB's. Would like to get this started locally, but having trouble convincing club leaders this is even a thing. Hate to admit it, can't find anyone else doing it.

Nor real positive on this, but I think part of the 4H shooting sports muzzleloading includes a silhouette match. Might want to see if there's a 4H shooting sports chapter nearby and check with them.
Otherwise the closest thing you'll get would be the typical muzzleloader shoot where you shoot at various knock down or swinger targets.

Ridgway Rifle Club does, but it is only a few matches a year. I would love to try it. The 6hr plus drive for a 20 round match is too much though.
Atglen Sportsmen's Club tried but the attendance was too low .