What did you use to punch?FWIW gents, I've been able to manage all of my contact materials using a solid straightedge and a utility knife. As ong as you take it slow with even pressure and stay in the same score line, you'll get through in a few passes. At least far enough to be able to *snap* along the scored edge.
You don't lose material and your edge is straight & clean, only a small amount of edge buffing is really necessary.
This is 28g silver cut using this method and I've only taken the burr off the edges...
FDA BOC