Have any of you guys used any of the black powder substitutes (777, Shockeys, Pyrodex, etc.) in your flinters?  I shot my .58 Enfield this weekend with 777 for the first time, and was absolutely AMAZED at how little fouling there was with it.  In my 40 cal flinter, I continued to shoot Goex FFFg, with FFFFg in the pan.  Just wondering if I might be able to get by with BP in the pan, and a substitute in the bore.  The thought of doing an extraction makes me want to fire a blank load first however.
And, I'm going to shoot next weekend, and know I won't be able to get at cleaning my rifle for a good 6 hours after firing it, other than the bore patch thing.