No.. and I don't intend to try, but I have fixed an insane amount of things with JB Weld. I think it would work. If it was for a range toy, a gun you'd never be depending on to defend yourself or do any serious work with then I'd try it just for the hell of it. I'd bet it works fine and you never have a problem.
If it was a gun I planned on counting on.. I'd never feel 100% about it though. Well.. not for a few years anyway ; )