Can you shoot a 9mm round from a 380 handgun?

Answer 1

Although the two bullets have the same diameter, one cannot shoot a 9mm Parabellum round from a .380ACP pistol.

The .380acp is called a 9mm short in other countries. Its case is 2mm shorter than the 9mm Parabellum. This means that if one chambered a 9mm in a .380, the breech would not be fully seated. Often, modern handguns would not allow the trigger to actuate the hammer due to a disconnector.

If one were able to get a hammer to fall, the design of the .380acp pistol is meant for the chamber pressures that .380 ammo produce, the 9mm produces much more pressure. The result would likely be a severe malfunction, maybe even a explosion with bits of gun flying off like shrapnel. The shooter would like be injured, how severely would depend on how the gun parts fragmented.