Bob McBride
54 Cal.
Celebratory gunfire is actually a real thing that kills people, it is all to do with the bullet striking the skull. Luckily not an issue in my part of the world.
I don't doubt it at all. I only suggest that the physics require the gun to be fired at something like a maximum of a 45 degree angle. Fired straight up, the bullet stalls and all the speed it can pick up after that is about 125 mph. At an angle it doesn't lose all it's momentum and can then strike someone at lethal speed. A skydiver can put their body at a 45 degree angle and their body acts as a wing, overpressuring at the top, and they can move at speeds of 300-400 mph but flat and straight down it's 125 mph all day long.