Reminds me of a story I heard about a friend of a friend (so grain of salt and all) who worked as security at a nuke plant. They've got a well-stocked armory and he liked to borrow guns to shoot with in his back yard.

He had brought a .50 cal rifle home and was shooting cans or something with a hill as a backdrop.

Then the cops showed up. Turns out the bullets were going through his targets (assuming he was hitting them), then passing right through the hill and hitting a house on the other side whose occupants called the police because they thought someone was shooting at them from the hill.

Not sure if anything came of it afterwards, though I remember he wasn't allowed to borrow guns from that armory anymore.