I removed the scope and rail from a Mod12 to install a new barrel, stripping the heads of the screws in the process. I have spares. Blue loctite was used. The threads are pretty packed with the dried yellow/brown loctite. I want to chase the threads with a 6-24 tap, but getting it started didn't go well. I tried bore cleaner and alcohol to hopefully loosen the dried loctite, with little success. I have used a tap before, but the threads weren't nearly as caked as these. What can I do to soften the dried loctie? I know that some use no thread locker on their mount screws, but I'd like to use it. Has anyone used purple loctite on their mount threads with success? What about just using an anti-seize compound? Thanks.