State attorneys general urge U.S. ATF to discard proposed ammo ban – The attorneys general of Montana and 22 other states are urging U.S. firearms regulators to drop a proposed ban on a type of ammunition popular with shooting sports enthusiasts but which regulators said could be used by criminals to harm police. The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives last month proposed prohibiting the manufacture and sale for the general public of a certain type of military-grade ammunition, M855 5.56 mm, widely used in the AR-15 rifle, because it can pierce protective vests or soft body armor worn by police. The bullets have for decades been exempt from federal ammunition prohibitions designed to protect law enforcement agencies from armed criminals because the cartridges were geared toward rifles used mostly for shooting sports.