Perhaps you know of pneumatic weapons also called airguns, but for those who don't; they're weapons that use air as propellant to launch a projectile rather than for example black powder or smokeless powder. They've been used as battlefield weapons, the most notable is probably the Girardoni air rifle https://en.wikipedia.org/wiki/Girardoni_air_rifle , but others such as the Kunitomo air gun https://en.wikipedia.org/wiki/Kunitomo_air_gun also existed.

They had some advantages and some disadvantages in that period of time, but eventually the disadvantages won out over the advantages. Air gun tech has come a long way though, so their capabilities have increased, of course so has their concurrents (such as smokeless powder) their ability.

My question is as follows. How could weaponry that uses air as a propellant become the norm for a military force? What kind of limitations (environmental/logistical/industrial/scientifical/economical), preferably no theological would be required to make a society favor fielding pneumatic weaponry over conventional weaponry?

I can only think of a subterrenean setting due to the noise reduction and shorter ranges involved, however I would like to also keep this above ground the norm. Not only that I would like stuff like Man-portable anti-tank systems (though stuff like PIATs and panzerfausts would also be in use), mortars and artillery to also use air as propellant.


Things to keep in mind:

-The setting in which this is to be used is semi-(post) apocalyptical, so mass production is not really an option; cottage industry exists and people would be familiar with modern techniques (though for obvious reasons stuff that requires computers and such is not feasible).

-People know about smokeless powder, black powder,...

-There are monsters in this world, so maybe they can play a role, but I feel like they shouldn't be the only reason.


@TheDyingOfLight That's not a bad thinking route you're using there.

@KerrAvon2055 Biggest armies (not including coalitions or alliances) are regiment sized, biggest battle will be fought at battalion size and most combat (90%) squad to platoon size. Though most of these people will not be professional soldiers, but conscripted/levies. Reasons for fighting vary, most of it boils down to I want what you have.

As for the monsters; varies greatly. There are things that are not any or barely sturdier than humans to things that could use a bazooka or 50 call. to bring down and then there are those where you better use flamethrowers or more specialised stuff (like magic (haven't worked that out yet) or certain elixers).

The terrain featured shall be urban, forest, swamp, subterennean and something like the Scottisch highlands.

@JBH I really enjoyed your comments. As you said silence is a bit of a problematic advantage since the compressors are quite the opposite.

@GrumpyYoungMan Yeah, I know that pneumatic can't match conventional hence why I am trying to find ways why people who know of smokeless powder don't use it in favor of air. On the other hand if everybody is stuck with pneumatic then everyone suffers from the same issues. The only way something like the long Tom could be fired seems to me if they're using it as a stationary emplacement with dedicated facilities something like the V3 was meant to operate in WW2. That said I am probably going to allow them to have crude rockets whether they're powered by blackpowder or something else is still something I am thinking about.

@Duncan Drake The location is not really based on any place on Earth really, it could be, but it's not like I am ever going to say "Northern America" or something like that. In fact I am probably going to make the place a sort of alternate dimension and hint at that. I just don't want to do stuff like in this dimension you can't make gunpowder work, because I feel like that's a bit of a cop out. One thing though that may be important is that the place is often very foggy or at least misty. Maybe that helps a bit to off set the lower range of pneumatic rifles. So yeah, no ammunition imports.

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    $\begingroup$ Just to point out a problem (and to quote one of my favorite movies): Can you fire an ICBM horizontally? Sure! Why would you want to? (The Hunt for Red October) You are either carrying a heavy bottle of compressed gas around (a very limited resource) or you have whomping good compressors built into the weapons, which is believable - except that compressing air, even if the equipment is perfectly silent, isn't. Especially at the speeds you'd need for automatic weapon fire. Your soldiers would have big targets painted on them. (*continued*) $\endgroup$
    – JBH
    Nov 29, 2020 at 22:32
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    $\begingroup$ "Sssshhhh! What's that sound, Jackson?" "Sarge, it sounds like my cousin frankie suckin' down a slurpee!" "Open Fire!" Now, to be fair, gunpowder isn't exactly stealthy, but the "reload time" and "reload sound" is something that would be fun to consider in your story. I'd hate to be the guy carrying the bazooka after he's fired it. At least for the time required to recompress the air. You know, the more I think about this question, the more I like it! +1! $\endgroup$
    – JBH
    Nov 29, 2020 at 22:33
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    $\begingroup$ The barrel pressure of a M1 artillery piece when firing is around 40,000 psi (en.wikipedia.org/wiki/155_mm_gun_M1). So, pneumatic artillery would need to store enough gas at 40,000 psi to launch 100lb artillery shells repeatedly, i.e. quite a lot. That would be an extraordinary engineering challenge with the best materials that exist today. Attempting to literally can a detonation with cottage-level industry is well into the realm of fantasy. (Also, to respond to a different comment, firing pneumatic artillery at such pressures wouldn't sound any different than regular artillery.) $\endgroup$ Nov 29, 2020 at 22:58
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    $\begingroup$ (continued) A longer gun barrel to increase the acceleration time of the gas pressure lowers the pressure requirements for pneumatic artillery/firearms but at some point the length becomes unmanageable or the artillery barrel starts to sag under its own weight. So, tl;dr, pneumatic mortars are plausible but artillery isn't. (And anyway, if there's enough explosives to fill the immense # of shells needed to make mortars/artillery barrages work, they'd be far better used as propellant in ammunition for small arms.) $\endgroup$ Nov 29, 2020 at 23:05
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    $\begingroup$ @JBH My secret superpower is "being a wet blanket" but, fear not, I have pledged to use it for good (worldbuilding, that is) rather than evil. $\endgroup$ Nov 30, 2020 at 3:00

3 Answers 3


No Dangerous Chemistry Required

In a post-apocalyptic setting that brings the society back down to cottage-scale industry, gunpowder becomes a finite resource. The chemistry involved in making safe, reliable smokeless powders is complicated and involves noxious, caustic, or volatile precursors, as well as processes whose failure modes involve very loud explosions. Many early nitroglycerin and nitrocellulose factories were completely destroyed due to accidents. Even black powder manufacture requires chemical precursors which could be hard to find or manufacture in the required concentrations and purity in a post-apocalyptic setting.

Safe production of an airgun, however, is well within reach of a reasonably-equipped machine shop. Compressors would be available via salvage or new production, and pressure-rated bottles can be found everywhere, in sizes ranging from CO2 cartridges to SCUBA or welding-gas tanks (or even larger).

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    $\begingroup$ Whilst I do want to thank everyone who has answered the question for all of the answers helped me a bit (I am a believer that several different factors would be required for pneumatics to thrive) I do think this one is the one most usefull in my specific setting. Black powder is not really superior to pneumatics in most situations present in the setting and that what could be produced would be better used in stuff like rockets and the resources put into a smokeless powder industry would probably be better spent on other industries. $\endgroup$ Dec 3, 2020 at 0:37

First, what are the advantages of air guns?

  • Good for stealth. The Wikipedia Article on air guns mentions that "they did not disclose the shooter's position or obscure the shooter's view, unlike the black powder muskets of the 18th and 19th centuries." Probably similar with-gunpowder weapons could be made, but I'm not a gun expert. Wikipedia also notes that they could be deadly in the hands of a sniper because of their quiet nature. It says that "France, Austria and other nations had special sniper detachments using air rifles."
  • Cost-efficient. There's no use of gunpowder, so that's a bit saved on every shot. It probably wouldn't be much in our world, but maybe in yours the resources to make gunpowder are more rare or difficult to make. (or, as you mentioned, mass production is not an option which might make gunpowder more costly)
  • Versatile. Air guns can be used in all kinds of different environments. Guns with black powder, for example, have issues with getting wet, and there are probably similar restrictions for other powder types (as I said, I'm not an expert). Your world could have a lot of environments that make gunpowder an issue where air guns wouldn't be (you mentioned swamps as a battleground, which would be a problem for black powder because of the water). My favorite example is what I'll go over next.

I have to mention what I think is possibly my favorite gun design I've read about: the air rifles in Twenty Thousand Leagues Under the Sea. These guns are designed to be used for hunting underwater which I think is totally awesome. The reason Nemo chooses this type of gun is that he cannot manufacture powder from his submarine (as I said, this is resource-effective), but my favorite part is that he makes up for the slow speeds they'll have so far underwater by electrizing the balls. If one of them so much as brushes against the target, it is lethal and the animal drops dead from an electric shock. Now, this might be possible with gunpowder weapons, but this is the only example of the idea I've seen. (You could also replace the electricity with some sort of magic thing, I don't know how your magic system works)

I hope this gives a few ideas. If these don't work, let me know and I'm happy to come up with something new.

  • $\begingroup$ Actually underwater spearguns use compressed gas (or elastic bands) to propel their spears to this day. Jules Verne knew his stuff. $\endgroup$
    – AlexP
    Nov 30, 2020 at 14:05
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    $\begingroup$ Re: spearguns, interestingly, airbows (pneumatically fired arrow guns) capable of taking down game exist, e.g. crosman.com/airbow . Perhaps if the OP can come up with a in-universe reason that an arrow would be better than an airgun pellet, they could use airbows instead. $\endgroup$ Nov 30, 2020 at 16:47
  • $\begingroup$ @AlexP Yeah, somehow Verne's ideas keep finding surprisingly accurate details. Here's an article I found that points out similarities between Verne's From the Earth to the Moon and the actual Apollo 11 mission. The one that most amazes me is that "A competition for the launch site would ensue between Florida and Texas." I guess Verne was just really good at looking at which places would work for such a launch and how it would go down between them. I know that's kinda off-topic, but I couldn't resist sharing. :) $\endgroup$ Dec 1, 2020 at 0:18
  • $\begingroup$ Note that much of the noise of a modern firearm is due to pushing the bullet past the speed of sound (suppressors - aka silencers, which are not as effective as shown in movies - work primarily to decrease bullet velocity). This means that airguns are only quieter if bullets stay slower than the speed of sound, which puts an upper limit on lethality (velocity imparting more energy than mass). $\endgroup$ Dec 1, 2020 at 5:34
  • $\begingroup$ @Clockwork-Muse In that case you could use the idea I mentioned Jules Verne writing about of electrifying the bullets. That way even at low speeds they could impart lethal damage. Though it wouldn't work as well with people with clothing, you could probably figure out some other way to coat it or use whatever magic system the OP has to set up something $\endgroup$ Dec 1, 2020 at 5:59

Market dominance, tunnels and sniffer monsters

There are three reasons I can think of for air-powered small arms and low-velocity support weapons to be prevalent in the environment described. (Sorry, but @GrumpyYoungMan is correct that the technology is not feasible for serious artillery. Cottage industry would also be struggling to build 155 mm guns and their ammunition.)

First point - the best technology is not always adopted. The person with the best marketing typically wins, especially in a "cottage industry" level where there are not going to be competing corporations with professional marketing teams. All it takes is for there to be a bad experience with the only competent chemist blowing their hand off while trying to manufacture primers while a highly competent air gun enthusiast gets a production line going and air guns will be first choice for one enclave at least. (Hard to apply the same set of circumstances to all the nations, but if one enclave starts selling the air gun equivalent of the AK-47 to everyone then it will become dominant.) The ammunition will be very simple to manufacture compared to projectile + cartridge case + powder + primer, with no one in a position to contest the manufacturer's claims that the increased maintenance on the air gun seals is less than the increased cost of gunpowder ammunition.

Second - air guns are much safer to use in poorly ventilated areas. If a significant amount of the fighting is occurring in tunnels, basements or small rooms, the ability to not asphyxiate yourself while shooting is a major advantage. I realise that most of the terrain mentioned was open ground fighting, but if useful technology / resources are in underground caches and basements then there may be fighting going on there. (The reduced peak decibel level of the airguns is also beneficial, as noted by Benjamin.)

Finally - one idea that was proposed several decades ago was to create venomous insects that would home in on the odour of the brand of gun oil used by enemy forces. This was a silly idea - it would take much longer to design and breed the insects than it would take for the enemy to change brand / aroma of gun oil once they learned of the threat. However, what if one of the pre-apocalypse factions was practising asymmetric warfare and had no conventional forces at all? Create a bunch of venomous insects (let's say wasps) that home in on all gunpowder combustion products and suddenly having lots of gunpowder guns does not look like such a huge advantage. Assume that these insects have become ubiquitous in the relevant area since the apocalypse.


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