I have an H&K usp 9mm an finally took it out shooting again, the other day. I brought it back home and the weirdest thing happened. The front sight white dot came out or off. Not the whole sight just the white dot. They are the factory sights 3dot. I have no idea how or what made this happened. Has this ever happened to you? I can not take a good picture of it right now to explain it well.