RE: Goex FF ?
sam52 Triple Se7en will work real good for you as will Pyrodex RS as long as your not talking a T/C Hawkins Flintlock. If it is a flintlock then you would not want to use the other powders....
I shoot Triple Se7en out of my CVA Mountain Stalker and with 80 grains of T-7 a wonderwad and a .530 patched round ball with a .018 pillow tick patch it is a great shooting rifle.
good luck