I am a long-time shooter but new to Black Powder.
I recently purchased an H&R Huntsman .58 cal. The previous owner made a bronze bushing that allows for the use of 209 primers. It looks like a solid setup but, with the large hole for the 209 primer, how can I use powder granules without them pouring into the primer hole, plugging it, and possibly jamming the firing pin? I'd prefer to use loose powder but if pyrodex or triple 777 pellets are my best choice, do I need pellets specifically for .58 cal or can I use .54 or .50 cal pellets as long as I use the correct charge for the ball?
(Sorry for the crappy cell phone photos)
Bronze 209 adapter
Adapter inserted into breech plug
P.S.: I've read all of the safety concerns with the o-ring breech plug and I understand the risks involved.