I'm wondering if a world, given the capabilities of at least early 20th century industrialization, but without any substance equivalent to black powder/gunpowder would go about producing ranged weapons. I understand air rifles exist, but would they be the primary instrument of armies?

  • $\begingroup$ We don't know if they would or when, nobody can answer that, but one could give you alternatives . The good thing about this being unanswerable is that You can have it any way you like $\endgroup$
    – Raditz_35
    Jul 17, 2018 at 8:21
  • $\begingroup$ Are you seeking answers for alternative compounds to gunpowder, or mechanical alternatives? $\endgroup$
    – Reactgular
    Jul 17, 2018 at 13:51
  • $\begingroup$ Mechanical or electrical alternatives $\endgroup$
    – knowads
    Jul 17, 2018 at 15:46

4 Answers 4


Possibly using motorised flywheels, like a pitching machine but instead of pitching single baseballs it fires shells or bundles of steel darts, for larger installations. The crossbow is still a worryingly effective weapon given modern construction techniques and materials crossbows, and even bows but they're harder to use, can be quite efficient even in the face of modern body armour.

I would expect to only see air or spring powered rifles for extended long range applications, sniping the enemy officer corps for example.

  • $\begingroup$ Glad you mentioned crossbows especially if made with modern materials & fabricated industrially. First thing I thought of, but you got there first. What about artillery-sized crossbows launching giant explosive-tipped bolts? Plus one. $\endgroup$
    – a4android
    Jul 17, 2018 at 13:00
  • $\begingroup$ @a4android You could use something like a scorpion (you'd want a modern bow obviously) but I think a wheel based mechanism would be more compact for a given throwing range if more reliant on an external power supply of some form, an explosive bolt is more potentially awkward than a round shell but also has more impact energy, there's pros and cons on all sides with that one. $\endgroup$
    – Ash
    Jul 17, 2018 at 13:06
  • $\begingroup$ That's nifty! I didn't know about the scorpio siege engine weapon. That makes sense. Most weapons have their various drawbacks. Delighted to learn something new, very grateful for that. $\endgroup$
    – a4android
    Jul 17, 2018 at 13:13
  • $\begingroup$ @a4android No worries, I can't remember what the Chinese version of "giant siege crossbow" is but they apparently had a version that could fire several bolts in quick succession. $\endgroup$
    – Ash
    Jul 17, 2018 at 13:17
  • $\begingroup$ If you have explosives for making "explosive-tipped bolts", you have propellant for firearms. $\endgroup$ Jul 17, 2018 at 15:46

Not air rifles, but steam powered weapons. See for example the Holman Projector, actually used in WWII.

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    $\begingroup$ The Holman projector relied on firing an explosive charge, without gunpowder that is a problem. It was also of limited effect. $\endgroup$
    – Sarriesfan
    Jul 17, 2018 at 8:27
  • $\begingroup$ @Sarriesfan could the principle not be used for other purposes than anti-air? Couldn't you accelerate a projectile horizontally? $\endgroup$ Jul 17, 2018 at 8:29
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    $\begingroup$ @ArtificialSoul To give an example when the Mythbusters attempted to create a steam powered machine gun m they found beyond point blank range it could not fire a projectile with enough force to kill.m.youtube.com/watch?v=Y3cRNEyUTF8 It's also a large weapon too large to be anything other than a field piece air rifles could be man portable. $\endgroup$
    – Sarriesfan
    Jul 17, 2018 at 10:46
  • $\begingroup$ @Sarriesfan okay, that is a good point. $\endgroup$ Jul 17, 2018 at 11:05
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    $\begingroup$ Without a bit more detail/summary work this is really verging on a link-only answer. $\endgroup$
    – Ash
    Jul 17, 2018 at 14:09

For personal armament, airguns are the way to go.

Air-powered weapons are a surprisingly simple technology- the Girandoni Air Rifle was developed in the late-1700s and used militarily by Austria in the early-1800s. It had a muzzle energy comparable to modern hunting crossbows, but could fire at a very high rate with accuracy and significant killing power.

This is an example of an airgun being militarily viable and competitive with firearms, over two hundred years after crossbows were rendered obsolete. With firearms out of the equation, crossbows are not likely to make a comeback- technological developments into the 20th century made airguns more powerful and, more importantly, logistically easier to manage.

They're simple, accurate, easy to use, more powerful than a crossbow (some modern airguns are capable of 1kJ or more of muzzle energy), and capable of a much higher sustained rate of fire. The primary disadvantage is the reliance on finite air pressure, but this can be mitigated with swappable air tanks, a single large reservoir, or an air compressor.

Fundamentally, the difference between firearms, airguns, crossbows, pitching machines, and any other sort of projectile device comes down to the source of propulsion energy. Firearms are extremely efficient and powerful through the use of chemical propellants, but if chemical propellant is unavailable, air pressure is the next best thing.

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    $\begingroup$ hydrogen is better than air for gas firing. it has a much higher compression rate then air so the bullet can go faster when fired, more bang for buck (but can be flammable) $\endgroup$ Jul 17, 2018 at 17:26
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    $\begingroup$ Unfortunately, hydrogen is also a logistical nightmare to produce, contain, store, and transport, which is why light gas guns have never gone beyond limited scientific use. $\endgroup$
    – Catgut
    Jul 17, 2018 at 18:19

Numbers have a quality of its own. Muskeets replaced bows not because they were better, but because they were easier to teach to use to untrained troops. Iron (steel) swords replaced bronze not because they were better, but because they were cheaper and iron ores were commonplace while tin ores were rare.

While there are ways of making gunpowder-less guns, they are all rather impractical. Just like laser guns, we don't use them because they're not practical, not because we don't know how to build one. Chemical explosives are a very convenient way of propelling projectiles. If you don't have these, the mechanical force of a bow is the next best thing. Other methods, like compressed air, steam or magnetic fields are far more expensive, clumsy, unreliable and/or failure-prone, so I guess your civilization would aim for state-of-the-art repetition crossbows.


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