Back in 2003 I build up an Isaac Haines flintlock in .40cal for target shooting and small game hunting. It wears a Colerain barrel and has always shot VERY well. Just recently I needed to change patching material so have been working on perfecting the load again and changing to the Dutch Schultz 'dry lube' system.
30gr 3Fg, .395 cast pure lead ball, 0.021 patch.
50gr Swiss 3Fg, .395 cast pure lead ball, 0.021 patch.
Both groups approximately 3/4 inch. The old gun still has it.
This is me a few years back shooting "Isaac" in competition.
Cheers from New Zealand