I use JB Weld on many of my precision shooting rifle build projects. First, clean the threads well with lacquer thinner and a small caliber bore brush. Coat the screws with wax shoe polish with a q-tip first, it acts a a release agent, then buff it off to leave a shinny coat. This will prevent it from bonding with the JB Weld. Coat the screw with JB Weld and put a little in the hole and thread it in. Wait about 18 hours and unscrew it. If everything was clean, it should look like a new threaded hole. Try one first and you be the judge. The JB Weld only cost you less than $5.