Online rumors about a big government munitions purchase are true, sort of. The Homeland Security Department wants to buy more than 1.6 billion rounds of ammunition in the next four or five years. It says it needs them --roughly the equivalent of five bullets for every person in the United States -- for law enforcement agents in training and on duty. Published federal notices about the ammo buy have agitated conspiracy theorists since the fall. That's when conservative radio host Alex Jones spoke of an "arms race against the American people" and said the government was "gearing up for total...