True, but that was an aimed shot. This was an idiot pointing his gun up in the air and pulling the trigger. With that higher trajectory the round will have no problem traveling a further distance.
Modern muzzle loaders can easily shoot a 275 gr 45 cal bullet at 2200 fps which according to my balllistic program will go 2500 yds when fired at an angle of 12.5 degrees and will still be traveling near 400 fps on impact.
Bottom line is no matter what the firearm always fire into a backstop. I unload my muzzle loader by firing into my target on my range at home.
Also there are muzzle loader bullets such as Powerbelts that do engage the rifleing an could be identified as from a specific gun.
When I was a teen, we lived in a declining neighborhood. One day a bullet whizzed over my bed and went through a poster on my wall. The police said it could have come from anywhere in the hills and couldn’t [or wouldn’t] trace it. That incident was the last straw that convinced my parents that it was time to move.