If I remember correctly, the only reason they developed the gyrojet was because firing a gun in space would send the shooter flying off as well. Otherwise so long as the round was sealed properly, you still had oxygen in with the firing cap and gunpowder to operate.
You don't need any oxygen in the casing whatsoever. All gunpowders contain their own oxidizers: potassium nitrate in the case of the long obsolete blackpowder, and more modern smokeless powders are all nitrated compounds, usually the majority being nitrocellulose.
If I remember correctly, the only reason they developed the gyrojet was because firing a gun in space would send the shooter flying off as well. Otherwise so long as the round was sealed properly, you still had oxygen in with the firing cap and gunpowder to operate.
You don't need any oxygen in the casing whatsoever. All gunpowders contain their own oxidizers: potassium nitrate in the case of the long obsolete blackpowder, and more modern smokeless powders are all nitrated compounds, usually the majority being nitrocellulose.
No. The recoil impulse of even dumb&slow cartridges like .45acp is minimal compared to a suited up human.