This isn't the fucking 1800's. You don't have to worry about being forced into a duel while out getting smashed with your buddies.
But in all seriousness, I'm on the fence on this one. Since a bar in of itself typically serves only drinks its fair to assume most patrons are going to be consuming said drinks. While SOME might be responsible with their firearms, not all will. Alcohol impairs your actions, obviously why you can't drink and drive etc etc, so I'm inclined to think guns + alcohol = bad.
On the other hand, I have a great fucking idea.....let the owner of the establishment decide. If they agree to it, but then can't control shootings / violence in and around the establishment......the state can revoke his liquor license.
He would have to carry more insurance, probably hire armed security which increases costs, and he'd have to look at arming his staff as well....so I can't see many businesses okay with it, due to the additional burden placed on them to operate and if I were a business owner I shouldn't be forced to let someone in who's packing heat if I don't want you in my establishment.