If you're wondering how it's even possible to shoot a gun underwater, gunpowder contains oxygen — a key element in the firing process — the gun still goes off exactly as it would on land.

Can you use guns underwater?

No, you should never fire a gun underwater. ... There are some pretty common things that happen to guns underwater. Water causes issues with the ammunition, the action, and the projectile ballistics. Once you get your gun underwater, the barrel almost immediately fills up with water.

Do guns get ruined in water?

Firearms and ammunition are not intended to be subjected to total immersion in water. They are very susceptible to moisture damage, especially metal parts that will sustain rust when moisture is left untreated.