I have a son who I believe may be hidding, lets just say something he should not in his gun safe. I know that he barely turns the dial after using and have herd that if not spun many time it can be manipulated simply is this true.
Ask your son to open the safe in front of you and show you the content. That's how I would solve this situation. A good father doesn't spy his son secrets, but honestly explains him his reasons and set a good example.
Either way, I'm sorry... but we're not going to be able to offer any real help on manipulating gun safes in the public forum. (Otherwise, the next son who wants to get a gun out of his Father's gun safe would find this via Google, and have a nice set of instructions.) Hope you understand...