Buddy of mine came VERY close:
Went to gun show, got a rifle he'd been drooling after for years, enjoyed gun show with family. Among others, his son, son-in-law, etc. were around. They get back from show, go shooting and try out the nice BLR .308 rifle, then back home. He cleans the rifle and hangs on pegboard in his gun room, removable magazine loaded, but nothing chambered.
Dad comes over that night, and they tell him about the recent acquisition.
Long ago, his Dad was a champion level shooter in military. But Dad is losing it a bit these days. He's noticed a few things at the range that made him wonder...
Dad goes and gets new rifle, takes into living room, works action without checking, aims at big screen TV and pulls trigger. S.A. surplus FMJ .308 goes through TV, through wall, blows bits and chunks as it cruises through bedroom behind wall. My buddy's one year old grandson is hit by something. Panic ensues, blood, commotion, etc.
They were lucky. Kid got full treatment including chopper to trauma center. Turns out he was just winged by a flying fragment, as far as anyone can tell. He's fine. But that's about as close as you can come to having head blown off and still be OK.
My buddy is a "preparedness" guy, but that gun "ready room" not always locked away from the rest of the house, with magazines (but not chambers) loaded, turned out to be a bad idea. I hope he's realizing that this works for "Burt" in the first Tremors movie, but not so well in real life.
No charges filed, but my buddy still isn't sleeping all that well.
Not staying on top of Dad's declining faculties was a bad idea. NOW he's aware that Dad is not the safe handler of guns he once was. You may not expect it from family members who used to be responsible, but Mr. Murphy never sleeps...
If some fool can get to your house gun, eventually some fool will. Plan accordingly. Sure glad the little guy is OK. But now my buddy is on "their" radar...