KINGSPORT — Local gun store employees do not believe a proposed ban on certain ammunition will be passed and say even talking about a ban has caused the ammunition to sell out in their stores.It was announced on Tuesday that the Obama administration is considering banning some types of 5.56 mm rounds — or .223 caliber — which the administration says can pierce protective vests worn by law enforcement officers.Last month, the Bureau of Alcohol, Tobacco and Firearms released a 17-page proposal to ban the ammo, which has been under consideration since 2011.