How does JB Weld hold up to the vibration and concussion of a Magnum? I know that JB Weld is good stuff, but I have also had problems with it not standing up to vibration real well. Now I have never used it in a gun, mostly just on mechanical parts. Dont get me wrong either, this is just an honest question and I am not questioning your expertise or methods. I know that with the proper preperation JB Weld can be an excellent filler.