My neighbor accidentally put a .44 Magnum round though my wall. It missed my head by three inches. It started in his bathroom, went through the mirror, went through the closet on the other side, blew through that closet door, traveled across his hallway, blew through our common wall, richocheted upward off my computer desk, and lodged in the doorframe.
The narrator is familiar with guns, and there are pictures.
He reports that his neighbor owns two .50AE Desert Eagles, a .357 Magnum, the .44 Magnum, as well as "a 5.56mm M-4 carbine, a Bushmaster 5.56mm AR-15, a Czech 7.62mm AK-47, a 7.62mm German G3, a Belgian 5.56mm FN-FAL, about half a dozen Glocks from 10mm on down, a .44 Automag, a Heckler & Koch MP5, and a Barrett Light Fifty .50 cal sniper rifle and a .454 Casull on order."
There's a good amount of money in those guns. A Barrett M82A1 costs close to eight thousand dollars. I don't know why somebody who feels comfortable enough with his finances to buy one is renting.
One theory of the incident is that the neighbor accidentally discharged a round while practicing his draw. Based on the location of the entrance, I suspect it's at least as likely that he was posing, checking out how cool he looked, and decided to dry-fire without verifying that the weapon was unloaded. And that, folks, is how negligent discharges happen. An officer on the Border Patrol was killed in a similar incident in the late fifties, and some stories have it that it was the great gunwriter and fast-draw Bill Jordan who pulled the trigger. (Though no mirror was involved there.)
The really dumb part: the negligent neighbor is in the military, and he'd been trained better.
Gun safety rules: they're important for a reason.