I have an 1887 Paradox gun that somebody thought would make a good dedicated double rifle. So they soldered a ramp sight on the front. They also mounted a huge contraption for a rear sight. The rear was a monstrosity. I removed the rear sight and you can see what was left underneath in the picture below. The front sight is the worst of it and the result of the soldering was loss of regulation. The left barrel shot a nice tight group. The right barrel shot a nice tight group. The left and right groups were about a foot apart diagonally at 25yds. The gun is in the process of being corrected to include re-regulation.

Butchered front:

The front as it should be:

Butchered rear with the monstrosity of a sight removed:

The rear as it should be: