If the event has screening with a LEO present, and they notify you that you did not pass screening, then you must immediately leave. You can come back unarmed.
If you are wearing a large metal belt buckle and your gun is hidden underneath or in a Thunderwear holster, and if they are not making people take off their belts or clothing, then you can probably get in with your gun. As long as you have not been notified that you didn't pass screening, then you are still legal to carry concealed.
The GA Dome is considered a "government building".
If there is no weapons screening, then technically you can carry a pistol openly.