Congress established the U.S. Army Ordnance Department in 1812 to oversee the procurement and inspection of all weapons, components and ammunition purchased by the United States government. Previously, the function had been filled by a number of agencies operating under separate authority from the military and treasury. Colonel Decius Wadsworth, the first Chief of Ordnance, immediately incorporated the two national armories at Springfield and Harper’s Ferry into the new department.  

More about Harper's Ferry and its role