regulation by filing the muzzle
Actually, it is the other way around - file the side OPPOSITE from the direction you want to move the pattern/group. To move the pattern towards the center, file toward the outside edge of the muzzle; to move it up, file the bottom. It apparently does not take a lot of angle. File a little and fire for p.o.i.; then repeat until adequately centered. If desired, lightly recrown but be careful to get it even on the now-very-slightly-oval muzzles.
This comes up periodically on muzzle-loading boards and occasionally on shotgun boards. It is reportedly not uncommon to find old American-made doubles (breech and muzzle loading) with both muzzles angling back from the ribs - I've only seen one like this. Apparently, the Brits were more consistent about regulating doubles in manufacture, and without bending the bores to do it.
Hope this helps,
Joel
Actually, it is the other way around - file the side OPPOSITE from the direction you want to move the pattern/group. To move the pattern towards the center, file toward the outside edge of the muzzle; to move it up, file the bottom. It apparently does not take a lot of angle. File a little and fire for p.o.i.; then repeat until adequately centered. If desired, lightly recrown but be careful to get it even on the now-very-slightly-oval muzzles.
This comes up periodically on muzzle-loading boards and occasionally on shotgun boards. It is reportedly not uncommon to find old American-made doubles (breech and muzzle loading) with both muzzles angling back from the ribs - I've only seen one like this. Apparently, the Brits were more consistent about regulating doubles in manufacture, and without bending the bores to do it.
Hope this helps,
Joel
