The business end of an A-10 Warthog. A 7 barrel 30mm machine gun which fires 3900 depleted uranium rounds per minute. Depeleted uranium is used not because it is radioactive (it isn't), but because it is the heaviest metal you can use. When it arrives at about 2800 feet per second, the impact is profound. The plane was designed around the gun, which was designed to penetrate tank armour. That'll get your attention.
http://www.pbase.com/chasp/image/69712418