I was greatly entertained when the Myth busters investigated the question:
Can you be killed by a falling bullet shot upwards by merrymakers?
I saw a vertical air column made, and blown with three air nozzles.
They found it relatively easy to read the airspeed for a stably
floating bullet of various calibers. (around 100 mph)
They noticed that tumbling was the characteristic terminal flight mode.
I saw a projectile rig intended to pop bullets out of a tube towards
a specimen head (a pig's head) at 100 mph which showed that the bullets
bounced away.
I saw an interview with a physician who showed X-Rays of an imbedded
bullet which felled a person at home. The round was traced to a shot
fired a mile away.
I saw an experiment run at Mojave on a dry flat lake bed, where series
of shells were shot vertically upwards, and shielded observers listened
for the impact direction.
I saw several rounds recovered, and their penetration
depth in the lake bed measured (about 2 inches) compared with rounds
shot directly down to the ground.
(BB gun 3 inches; 9mm 6 inches; 30-08 12 inches)
I saw them try in vain to recover a 30-08 round fired upwards -
the extended trajectory allowed just too much downwind travel.
I finally saw a helium balloon hoist a bullet dispenser to 400 ft
altitude calculated as the distance to achieve the terminal
velocity (100 mph)
I saw them measure the impact hole length - 2 inches as before.