Gunpowder has it's own oxidizer, cartridges will fire even underwater if the case mouth and primer pocket were coated with sealant. There does not have to be air inside the casing, most modern cartridges are filled to max capacity with powder up to the base of the bullet.
The Russians also had at least one Salyut that had a secret gun mounted on board for shooting satellites.
I don’t believe that gun will fire.
Apparently there's a good chance they will. As long as the ammo is loaded in atmosphere, there's enough in there already.
Gunpowder has it's own oxidizer, cartridges will fire even underwater if the case mouth and primer pocket were coated with sealant. There does not have to be air inside the casing, most modern cartridges are filled to max capacity with powder up to the base of the bullet.
The Russians also had at least one Salyut that had a secret gun mounted on board for shooting satellites.