I've had a real tough time locating black powder in my area. I never liked Pyrodex, so when the 777 came out, I gave it a try. At that point, I only had side lock guns. The 777 seldom ignited properly, giving me a hang fire except on the rare occasion.
I finally got an in-line. The 777 works very well. The ignition is fine with the hotter 209 primer. The only drawback? It leaves a deposit in the chamber area that literally has to be SCRUBBED out!
THEN, I found a source for GOEX! HMMMM!? Two shots of FFFg through the in-line stopped this nonsense dead in it's tracks. The second shot was almost impossible to ram home. BUT, the fouling was easily scrubbed out with about 6 passes of a dry 20 ga brass brush.
Inline: 777
Sidelock: GOEX FFFg
About the only difference I can tell between the 777 and the GOEX is the 777 just don't stink as good!
Since finding the GOEX, I may get rid of the in-line and go back to my sidelock!
There's just something about that cloud of stinking white smoke that just trips my trigger! LOL!!!