I would caution you to NOT tap the gun, but to check the screw size. I had the same problem several years back and the screw was not the proper size. I wound up making a screw in the lathe and all was well. If you don't have the ability to do the job I'd highly recomend paying someone the relatively small fee to have the job done. It may prove much less costly in the long run. I feel it's best to always alter the least expensive piece when trying to do most repairs. A screw is certainly less expensive to whack on than a M 21 frame! Don Hansen.
