Nothing but real black powder. Never shot a load of any form of substitute b.p. in any of my rifles or shotguns. My go to brand for nearly 40 years has been Goex, but have used others, like Elephant, Curtis & Harveys, Swiss, etc. Elephant was really dirty, and I used it mostly in shotguns until it was gone. Having not shot b.p. as much for the last few years I'm not even sure if Goex is still available. I've still got several cans on hand.

I read on one of the ML forums that Goex in LA is in the process of being permitted for start-up under new management. That thread didn't detail the timeline.

BP only. GOEX or Graffs. And clean up is only one more step - soapy water before the clean water. I use in the basement two of the wives discarded dish washer plastic pails, one hot soapy water, the other hot clean water. First a Tornado brush to break up the fouling, then a patched cleaning rod with a damp patch and a couple of swabs up and down with the water treatments. A dry patch, then one with WD-40, and a final one with Rem Oil. Doesn't take but 5 minutes or so.

JMHO, if you're gonna shoot smoke, then shoot smoke. It's worked for a couple of hundred years and still works just fine now. And the way things are going you'll have to be like Charlie and make your own if you want to shoot anything.