Now you've done it. You banged your stock against a rock and have left an unsightly gouge. Start by following the steps to steam out a dent. That will minimize the gouge. At this point, you can either sand it until the gouge is gone, which will leave a dip, or use a two-part epoxy like Devcon. Mix the epoxy, fill the damaged area, let the epoxy set up for the time indicated in the directions, and then sand it down so it blends in.