Run Blackhorn and save yourself a lot of trouble. Premium bullets also seem to save a lot of headaches.
What he said, about the BH209 at least.
For me, Pyrodex has an unfortunate combination of being harder to light than BP and still corrosive. Some cling to it for reasons of their own, which is fine, but I never recommend it to anyone starting out. BH needs hot primers, a clear flash channel, and good bore resistance from the projectile for good ignition. Those things present, it's great stuff. 777 needs special, expensive primers to reduce the buildup of fouling in front of the chamber, and has gone bad on me for no good reason a time or two. Stiil, it works well when fresh, with good power.
If you can find it, real black powder is wonderful stuff, and not as hatd to clean as some seem to think. It can be hard to find locally. Fortunately, a guy near here has literally tons in his bunker.
