Alex.....when you say copper, are you talking about the normal hardware on a gun....trigger guard, buttplate, etc.? I have never seen one, but, I have learned that one cannot say it was never done. I have seen copper used to make a
repair. Allen Martin did a wrist repair by wrapping a thin piece over the glued joint and nailed the edges down......a super
neat job, it made a very interesting gun.........Don