I got a couple of "stupids". Not really gun-related.
Was having a BB-gun war. I was wearing a Western-brand hunting knife. My friend (the enemy) was standing next to a pine tree, maybe 30 feet away. I threw that knife - a beautiful throw, and stuck it chest-high in that tree, right next to him. In the second or so it was in flight, if he'd have taken a half-step to the right I'd have killed him dead. Oops.
Used to shoot bow-and-arrows in the back yard. Had some hay-bales set up as backstops. One day I was curious as to how far one would go. 30 pound bow. I held it up at about 45 degrees and let 'er fly. It went three yards away. Cool. I was thinking about that, this past Christmas, as I gave my granddaughters bows and arrows. There was no one in that yard when I let fly, and thankfully no one when it landed, but there coulda been. Someone coulda damn sure walked out in that yard in that two or three seconds it was in flight. Opps. Again.
Kids sure do stupid stuff. It's amazing more of 'em don't either kill themselves or someone else.