Which powder are you shooting???

The grains of FFF are smaller than the grains of FF...Since they are smaller, they burn cleaner and leave less fouling in the barrel...You should reduce your charges by about 10% to get the same velocities...In my .54 flintlock I have tried both FF and FFF in Goex powder...I get less fouling with FFF over FF and I also reduced my charge from 100grs to 80grs, giving me more shots per pound of powder...

That being said, if you are getting good groups with FF, there isn't any real reason to change...

There is no reason to change your primer to get good ignition...