Another vote here for the real stuff, the holy black, if you can get it. I use 90 grains of FFg behind my .50 cal rbs in a Lyman GPR flint gun with 0.010" patches. Shoots right where it's pointed at 50 yards. I don't shoot past that with RBs.
I have Pyrodex on hand as well as 777. Don't use them often. BP outshoots them - rifle, pistol, shotgun.
Pete