There was guy at the range last year with one of those converted. It shot bugholes. He let me shoot it my shot was right on top of his. Was thinking off doing it myself but already already have 7 muzzleloader and flintlocks.
Good luck with it I know you'll like it. There is a guy that machines the chamber out and installs a new breechplug at a very reasonable rate can't remember where or who though!.
Thing shot like a benchrest rifle with very low recoil using smokeless powder that they use in the Savage ML