Can a gun be shot under water?

Answer 1

Maybe.

Most will fire underwater- the cartridge contains powder that does not need air to burn. Some guns may even fire safely underwater- not all can (water blocks barrel). However, the resistance of the water limits the distance the bullet will travel to a few ft. The military of several countries have experimented with building an "underwater" gun" that had rather iffy success. There IS one specialized type of gun used underwater- called a "Bangstick". This is a long metal rod with one cartridge in a holder at the tip. Used as a last defense against sharks, when shoved hard against a shark, the cartridge fires. The bullet hits the shark, but more damage is done by the gasses generated by the cartridge firing, being blown into the shark.