If the bar is owned by a local government entity, you could assert preemption over any gun carry rule at all. But private owners are generally free to enforce rules of conduct, unless you can prevail on a novel theory, like maybe the common Law of Innkeepers provides you the right to remain armed.
But I'm not sure I would ever go intobar requiring wanding & searches for 2 reasons. 1. I would not put up with the invasion of privacy. 2. If the place is so unsafe as to need that level of security, why would I want to go there voluntarily, carrying a gun or not?