I have the Bonesmasher pistol and it says that one of the upgrades for it, Shotgunner, is to hit 500 enemies with a Flourish attack. Now I was under the assumption from Fable 1 that a Flourish attack was with a melee weapon but I know that in Fable 2 and 3 you can charge your ranged attack so the camera zooms in and will hit for more. Is that the type of flourish attack they mean, or do they want just the melee ones? Or both?

I think the rumble flourish alone should do it, but I don't know for sure.
 
Maybe shoot up a camp full of dudes with the rumble (no zoom/scoping) alone, see if the slider moved, if it didn't repeat with the scope/zoom till ya find the move ya need.