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.
50m/55y today.
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