Got a Real-World Weapon or Armor Question? Mk. VI

[fusilier]

Dude, Diamondeye was agreeing with you.

Actually he was merely speculating, that the gunpowder might have enough oxygen in it, or that you would need to supply more oxygen. You do not need to supply oxygen to any gunpowder that I'm a aware of. His post may not have been the best to quote when replying, but it was part of the conversation.

There are problems with guns underwater, but it's not due to lack of O2. It's the water itself mucking up stuff.

My understanding is that water is deleterious to most gunpowders. Probably to some primers too. As pointed out already there are other issues with firing a gun underwater.