So me and my buddy are currently working on a story that takes place on a different earth-like planet similar to when dinosaurs like Brachiosaurus inhabit the landscape. A few differences is that the 'Humans' that evolved on this planet are much stronger and faster thanks to the increased oxygen in the atmosphere. (33% of atmosphere to be specific)

The people on this planet so far have advanced in the renaissance era of technology. But instead of combustion-based firearms, they utilize airguns as the standard ranged weapon. Combustion weapons like cannons, blunderbusses and grenades are still in use. But guns as compact as the revolver would just make the gun explode and render it useless.

As for the question. Assume they had access to the same materials we did when we made our first renaissance firearms. Would they still be able to make them? and if so, can they be just as effective? and to go even further, could they even make them as compact as modern handguns and rockets? If This is true, what mechanical differences would we expect?

This question specifically asks if it's possible to develop the combustion weapons. The other question specifies something similar, but only the performance and possible differences.

How would modern firearms behave in a high oxygen atmosphere?

  • $\begingroup$ The answer to "Is X possible?" is usually "Yes, given the right conditions." These conditions seem right. People can be very clever - the final product may look rather different than ours, but people can develop them. $\endgroup$ – user535733 Jan 30 '20 at 13:20
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    $\begingroup$ It'd be nice if you could quantify "high oxygen". 25%? 50%? There's absolutely no reason electricity wouldn't work, and there's no reason that handguns couldn't be made to work either (though it might require some more tricky engineering). $\endgroup$ – Starfish Prime Jan 30 '20 at 13:21
  • $\begingroup$ "electricity won't work since it would overheat due to oxygen" ??? $\endgroup$ – L.Dutch - Reinstate Monica Jan 30 '20 at 13:33
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    $\begingroup$ "'Humans' that evolved on this planet are much stronger and faster thanks to the increased oxygen in the atmosphere." - they'd only have better endurance; their muscles wouldn't starve for oxygen as fast as ours. Physiologically unchanged, there's nothing to make them faster or stronger. Enhanced cogitative ability, perhaps, or at least a delayed delirium from deprivation. $\endgroup$ – Mazura Jan 30 '20 at 22:16

TL;DR: yes, you can make guns just fine. What will cause you problems are lubricants and seals, and in older gunpowder firearms, things like slow match.

The main issue will be that transporting gunpowder now becomes even more unsafe due to the greater chances of little sparks causing big fires. People wielding guns and operating cannon will be dangerous not simply because they are well armed, but because they clearly have little regard for their own safety!

On the face of things, there's absolutely no different, from the gun's point of view, from firing in a high oxygen atmosphere to firing in a zero oxygen atmosphere. The gun barrel and action will not be made of things that can easily catch fire, because that's a terrible thing to do for a firearm regardless of your atmosphere.

It is everything else that will cause you interesting problems, and that "everything else" affects wind-arms like your local equivalents of the Girandoni. This is because flammable things exposed to high oxygen concentration will burn more fiercely, and in both firearms and windarms there's a powerful source of energy. With gunpowder, this is obvious: you've got high pressure hot combusting gas.

With air weapons, you have an issue I know as "dieseling", though I'm not sure if that's an official technical term. Basically, under rapid pressurisation of gas you get heating, and if that gas contains oxygen and is adjacent to a fuel, that heating can be enough to cause ignition. This is how diesel engines work. It is also what can happen with lubricants in air rifles, producing a "muzzle flash" even in the absense of buring propellant. I daresay this will also affect seals and o-rings in your air weapons, and whilst modern seal materials and lubricants are available to handle high oxygen environments, your equivalent of the Renaissance will not have access to this kind of chemical engineering. Shooters beware!

Old-school matchlock firearms also run in to difficulties. The "match" in question is a suitable material that can ignite gunpowder due to its own heat, but remains hot between shots and is easily handlable without going out. In a high oxygen environment, slow match will have to be made differently to prevent it burning vigorously instead of merely smouldering. I think this is still achievable, but the safety benefits of real-world slow match will not be easily reached due to the depressing tendency of everything to burst into flame enthusiastically.

Rockets made of paper will also likely not work well, due to the increased likelihood of the wrapping bursting into flames. That's OK though, because metal rockets are much better weapons anyway, and will likely be developed sooner rather than later. Being an artilleryperson will be a much more hazardous job though. Rather you than me.

I have no idea what you mean about electricity not being workable. That makes no sense. It'll be trickier due to accelerated corrosion of metal and little sparks causing big problems, but that's all.

There's no reason that a suitably engineered revolver (or other small handgun) would explode. It won't magically be more powerful in a high oxygen environment (the oxidiser for the propellant is mixed in with it; it doesn't come from the atmosphere) and the only thing you'd really have to watch out for is hot gasses escaping from the cylinder gap and setting stuff on fire (like your gloves, or hands).


Burning of the gunpowder is no different in high-oxygen atmosphere - first, because it burns on itself, without contact or dependance to the atmospheric oxygen.

Same for rockets: they carry their own oxydizer and propelling gases are already burnt.

What will be different:

  1. Accelerated corrosion. Of everything. Most other materials will degrade faster, too.
  2. Accelerated self-ignition. If a large pile of coal self-ignites for a week, in your case it will be a day or a few hours, depending on the oxygen partial pressure.
  3. Internal combustion engines: smaller (proportionally to the oxygen partial pressure) and more prone to detonation.
  4. Fires: a lot faster, hotter and hard to manage. Probably good for metallurgy and bad for the firefighters.
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    $\begingroup$ I would add that it would be harder to find pure sulfur and coal in such environment. So it would be harder to invent gunpowder. $\endgroup$ – ksbes Jan 30 '20 at 14:03
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    $\begingroup$ Earth is already like that, very oxygen-rich at 21% instead of 12%. I remember my third uncle twice removed bringing a swing-set from the homeworld, and the thing turned brown in 2 years. I was like "you gotta PAINT things here..." $\endgroup$ – Harper - Reinstate Monica Jan 30 '20 at 15:02
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    $\begingroup$ Also acceletare oxidation. Of humans. But make so much better blues songs "every breathe I take I feel the burn inside". $\endgroup$ – SZCZERZO KŁY Jan 30 '20 at 15:24
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    $\begingroup$ @ksbes probably. But both coal and sulfur deposits form insulated from the atmosphere anyway. Then again, it is the saltpeter the limiting factor in making gunpowder. In oxygen-rich world, saltpeter deposits will form easier. $\endgroup$ – fraxinus Jan 30 '20 at 16:04

High oxygen creates a number of issues in your world you may want to consider.

First, oxygen does not burn. What happens as you increase the concentration of oxygen is it decreases the temperature at which combustibles are able to start burning. This means your combustible weapons would most likely require less fuel to activate. The rules around storage and safety associated with your weapon combustibles would be more strict than Earth's requirements OR your combustible users would be more scarred and disfigured from accidents.

Fires of any sort on your world would be hotter, burn faster and be more devastating than anything we see here on Earth. If anything, your inhabitants would be more cognizant of not using weapons that could cause combustion on impact, that could cause really bad damage on their opponents, but could just as likely blow back on them as well.

Second, oxygen at high levels is hell on your metals. It is bad on Earth, but doubling the concentration means that all those metal objects would rust and oxidize extremely fast.

One other note regarding your humans being "much stronger and faster", oxygen at high concentrations is actually fatal to Earth humans. Your statement implies that you think this stronger and faster is due to more oxygen. Our atmosphere has just the right mix of oxygen to other atmosphere elements for our bodies. An oxygen warning:

Prolonged exposure to high oxygen levels (>75%) can cause central nervous system depression: signs/symptoms can include headache, dizziness, drowsiness, poor coordination, slowed reaction time, slurred speech, giddiness and unconsciousness.

While your humans may be adapted and fine with your world's atmosphere, if you expect to include visitors from Earth in your scenario, most likely they would die rather quickly in your high oxygen world. I would also theorize that your humans would metabolize food calories faster as a result of the higher oxygen concentrations.. which means they would eat extreme calorie diets.


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