If you did not clean the factory metal preseveritive out that would explain it. If so scrub the barrel with Simple Green and boiling hot water [be carefull the barrel will get hot]or strong dish soap brush strongly with brass or stainless bore brushthen scrub with alk. cosmoline and its realitives are difficult to remove after they are burned in. I scrub new barrels with alk. then with boiling water and simple green before firing that first shot. Lee