A man who threatened a Walmart security officer, saying he had a gun, will serve 30 days in jail.The man, Jamie Watson, 41, entered a guilty plea to the reduced charge of assault and theft. General Sessions Judge Bill Locke sentenced him to serve 30 days of an 11-month, 29-day sentence and perform 30 hours public service work. His time will be served in addition to the time he owes on a Circuit Court case.Walmart security caught him as he was trying to steal items, including a Duck Dynasty coat.