I was wondering also. Lately, I've been posting on www.gunspot.com.
I live here in NCOWS country where they strive to be more authentic than SASS. This has caused much friction in the past. IMHO SASS sometimes is almost like revisionist history. I've been shooting blackpowder (the real stuff) in cartridge guns since 1982 when I bought an Allen Arms (remember them?)Henry. Lately I've fallen in love with my new Cimarron 1871-72 Open Top repro in .44 Colt. It is accurate and loves blackpowder, especially Elephant brand. I'm getting 1-1 1/2 in. groups offhand @ 15 yds. so far. Yes, as you can tell, I think smokeless has no place in cowboy shooting as it is not authentic and the reason I got into this is because I wanted to see how the old time guns really shot. In other words, history as it was & not how I wanted it to be. Blackpowder. Try it.