Re: Screwed up screw heads
You can't replace metal that was taken out, but you can move the metal back into the slot, somewhat anyway, by CAREFULLY peening the metal back into the slot as best you can without disturbing the engraving. This will leave you with an irregular slot. Set the screw head up vertically and using a slightly larger mill saw (on center) than the original slot, clean out the peening. You say you have some smithing knowledge so this set up shouldn't be too difficult for you. This is about the only chance you have other than replacing the screw to match. This procedure will leave you with a slightly larger slot, hoping that the master gunsmith that buggered up the slots in the first place didn't really decimate them.