Can a gun fire in a vacuum?
Now, it is known that combustion needs to take place in the presence of Oxygen. So this is why some shows like Firefly ("Our Mrs. Reynolds" Episode) stated that some guns have to be fitted with a vacuum case that allows a propellant-based slugthrower to be fired in hard vacuum, or it will not fire.
But, the reaction of the propellant going all the way back to basic black powder supplies its own Oxygen. In the case of Black Powder it's from Potassium Nitrate (KNO3).
So, which is accurate? Can it fire in a vacuum or can't it?