If electricity didn't exist or behaved differently, would a society be able to develop and reliably produce modern-level guns and other weaponry, like assault rifles and missiles?
I'm going to focus just on firearms here as that's what I know.
Let's look at production, as it's kind of pointless to design something if you can't produce it.
What goes into making a 'modern' firearm?
Metal is mandatory if you want it to be portable (as Mythbusters has proven, you can make a cannon out of a big log, but that's way too big to carry). For most mass produced guns, steel (often 4140, but occasionally other alloys) is the material of choice, because it's the cheapest option that meets all the requirements. Steel has, of course, been produced by humans to varying degrees of quality for millenia, so that's one thing off the list.
Most modern firearms also have the metal components specially treated to resist corrosion and abrasion. Standard methods include, in relative order of development:
- Bluing: Is a simple passivation process that produces a layer of magnetite (black iron oxide, or iron (IV) oxide) on the outside of the metal part. There are four main methods that have historically been used, but none of them 'require' electricity. The methods that involve heat (also the most efficient ones) can be made more efficient through use of electricity (electric heating is generally more efficient than using something like a forge), but still don't require it.
- Parkerizing: Also known as phosphating, is similar in many respects to bluing, but produces a layer of iron (III) phosphate. In most cases, it produces a distinctive satin black finish (if you've ever seen a Glock in real life, you would recognize the finish). Functionally, parkerizing is low temperature heat catalyzed chemical process, and thus also does not need electricity except for improving efficiency.
- Ferritic Nitrocarburizing: Also known by the trade names Tennifer and Melonite, this is much more complicated, and can't be simply explained by the production of a single compound. Unlike the other methods, which are simple enough to not require particularly precise control, ferritic nitrocarburizing is an extremely sensitive process. While the salt-bath method is technically possible without electricity, it requires sufficiently precise control that it pretty much needs electricity for any kind of reasonable results. The other methods all require electricity.
So, the protection of the metal parts would have to resort to (less reliable and less effective) older techniques.
Plastic is also very common in many modern firearms. Usually, it's used in the grip, the trigger, and other components that don't typically take heavy shock loading when the weapon is fired. With almost no exceptions though, pretty much anything you can find on a modern gun made of plastic could be made of either metal or wood, so this isn't an issue.
The next potential issue is tolerances. Manufacturing of a firearm needs to be reasonably precise for a couple of reasons:
- Accuracy. Lack of precision results in weapons that aren't consistently accurate (that is, the variance between individual weapons will be larger).
- Repairability. You have to have rather precise (but loose) tolerances if you want to have drop-in replacement parts like most modern designs (eg, AR-15's or Glock's) do.
- Safety and reliability. If things are off by too much in certain places (for example, the chamber dimensions), you end up with a gun that isn't reliable or safe.
Effectively, you need modern tooling to make modern guns. This is technically possible without electricity, it's just insanely difficult, and you won't' be able to get quite as precise as modern tooling is (modern stuff isn't limited by the precision of human visual acuity or fine motor skills, without electricity you do have those limitations).
So, given this, so far it's possible, but probably not for mass production.
Next you have to consider ammunition. The same requirements for precision tooling apply here, except it will mostly just hurt your accuracy. As far as materials, standard ammunition consists of:
- Lead: Easily doable, people have been casting lead since before they could produce steel.
- Brass (for the casing): Also pretty easy, though the exact alloy is important. For quality on par with modern designs, you need at least WWI era metallurgy skills, possibly WWII. Alternatively, steel works, though it's potentially bad for the chamber if it's too hard, and aluminum works too (but that functionally needs electricity to get any realistic quantity).
- Copper: Used as a casing for the bullet. Not mandatory, but makes it easier to clean firearms after use and reduces metal buildup in the barrel. This is just as trivial as the lead.
- Some particularly hard metal: Armor piercing rounds have a special hard metal core. Traditionally it's steel, but it could also be almost any other hard metal. Modern rounds may use titanium, tungsten, or even depleted uranium.
- Wax: Used in some ammunition to waterproof it.
So, basic materials are covered. That leaves the propellant, and the primer.
The primer is easy. Pretty much any metal styphnate or fulminate will work, as will any other shock-sensitive compound, so you have lots of options, most of which were readily available long before electricity.
The propellant is a bit trickier. Modern guns use smokeless powder, not classical black powder. Smokeless powder is complicated. For those who care about the specifics, the Wikipedia page is a good starting point. In short though, it's possible to make smokeless powder without electricity, but it's expensive.
Overall, is it possible to produce a 'modern' firearm without electricity?
I'd say it's a definite yes, but it's not going to be cheap. Looking to some modern designs that use no plastic, you're looking at about 800-1000 USD for a decent semi-automatic handgun with electricity involved. I'd expect that to almost double without electricity, and for the ammo costs to almost triple.
OK, what about more specific stuff like assault rifles?
I'm going to assume you mean a military assault rifle, not the politicized name for a 'scary weapon'.
An assault rifle is typically defined as a long gun (a firearm designed to be fired from the shoulder, thus having a stock) with selective fire capabilities (it can be switched between semi-automatic and full automatic, and usually also offers a burst-fire mode too in modern designs) chambered in an 'intermediate' cartridge (something less powerful than classical battle rifles like the FAL or M14, but more powerful than handgun cartridges).
The first 'modern' assault rifle was the StG 44, a firearm developed by Nazi Germany in 1942. If you want to go even further back, the 'first' fully automatic rifle was the Italian Cei-Rigotti, developed in 1900, and the first 'practical' fully automatic rifle was the American M1918, developed in 1917 just before America's entry into WWI. All three of these were originally produced without requiring any electricity.
So, yes, most modern assault rifle designs are possible without electricity (though do note that some designs that never really caught on, such as the H&K G11 would not be possible without electricity).
OK, what about all the stuff other people are saying you need electricity for?
In most cases, a lot of the things other people are claiming electricity is needed for for the production of firearms just need it for efficiency. Namely:
- Computer Aided Design: Nope, not mandatory for making a modern firearm. Drafting is a lost art at this point in our world, but there's no reason it would not be on par in terms of precision with what we can do with CAD software today in a world without electricity. Realistically, some designs would be out without CAD software, but most of them either never caught on in our world, or require electricity anyway (see for example the aforementioned H&K G11).
- Electric machining tools: Also not needed. Many such tools either exist in some steam powered form (for example, power hammers or lathes), or were developed when electricity was already ubiquitous but don't necessarily need it (for example, drill presses or milling machines). In reality, there's essentially nothing except the barrel and chamber on a modern firearm that you can't just cast instead of machining it, and the barrel can easily be machined by hand (in fact, people still do this in some cases, though it takes significant skill to get the rifling right).
- Alloying: OK, this one is actually possibly a problem if you want really 'modern' stuff like vanadium or titanium alloys, but such alloys are unnecessary for modern style firearms. As I mentioned above, most stuff is some form of tool-steel, usually 4140 or 4150. 4140 is a mid-carbon steel (that part is easy) with traces of chromium, molybdenum, manganese, and silicon, and low sulphur and phosphorus content. Overall, that is actually doable with old 1800's technology, with the appropriate knowledge, though the level of precision for the trace components would be well outside SAE tolerances. It doesn't need to be 4140 though. Any alloy with reasonably similar mechanical properties will work, provided it can be case hardened, which encompasses a wide selection of alloys.
So, yeah, overall, still very doable, just not at levels of production we have, and things would likely be significantly more expensive.
This entirely depends on exactly what you mean by "modern-level gun" and "missiles".
Weapons are very simple. Stamp out some metal parts and mix explosives and that is it. The "assault rifle" is a century old - the basic principles are even older and all that is updated is some better metallurgy and more precise machining (which just takes technological refinement).
Missiles are a tricky question because it depends on exactly what you mean by "missile". Rockets predate electricity by hundreds of years, but it would be absurd to expect modern guidance systems (by definition electronics are not possible without electricity). You would need a much clearer indication of what you intend here - a metal tube self-propelled by combustion is easy as soon as you have enough basic chemistry to make an explosive, while infrared or radar guidance packages are clearly not within scope.
As a general rule, think about the weapons used in the first world war - you generally don't need electricity for what was seen on the battlefield (obviously telephones are out but I'm referring to what the typical soldier actually carried), and any advances beyond that which are just refinements on the same theme are likely possible as well.
Yes to the guns, even an "assault rifle" is just a machine gun. This is an exercise in metallurgy, engineering, and chemistry.
Missiles are much more complex, and imply some sort of guidance system. Germany developed the V-1 flying bomb, using a pressurized-air powered gyroscope based auto-pilot. A "vane anemometer" was used as a odometer, to determine when the bomb had traveled far enough, and should descend.
Approximately 10,000 of these bombs were fired at England, and about 2400 reached London. So they do have some level of operational effectiveness.
Without electricity you will need to redesign the history of Humankind. For example: Tomas Alva Edison invented the light bulb in 1879, and in 1800 Volta invented the battery. You need to redesign the civilization without electric light and without batteries, so there will never be electric motors, or telephone, or any radio communication. Perhaps the most widespread machines on industry could be steam powered, however, I don't see why weaponry could not evolve. Even rockets or assault rifles, just with a slower development. We humans are very creative with our inventions. Actually we could built clocks before the electricity (see this Forbes article: https://www.forbes.com/2008/02/28/oldest-work-clock-oped-time08-cx_po_0229salisbury.html#49f13c0531f3
But definitely, everything will be sloooooower, starting with the communications: email, whatsapp or the internet will never exist. And with that, all the society evolution.
I'll disagree (in principle) with some of the other answers, at least as far as missiles go. (Again) in principle, some forms of guided missiles might be possible.
There exists a form of logic called fluidics which uses the flow of a liquid or gas to perform logic operations. This could be used to control a missile in flight, since it would use the same high pressure fluid both to perform computations and to drive the output actuators.
The concept was being developed at GE in the mid-60s as means of making smart artillery shells, since the final processor would be extremely robust, although some problems were experienced with Coriolus forces affecting the fluid flow. The whole idea was eclipsed by the explosive growth in electronics capabilities, but seems to be poised to make a modest comeback in some applications.
However, this only applies to missiles which are self-contained in flight. Anything needing either a command link or radar is going to be out of luck. Although even then, people's ingenuity makes absolute pronouncements hazardous. Homing doesn't actually require radar, necessarily: there was a peculiar military program which attempted to use pigeons as suicide pilots.
Missiles use electricity, They carry a high voltage battery to power the onboard gyrostabilizers and whatnot. Rockets however, can be ignited via a percussion cap and since theyre unguided they need not have any onboard power supplies.
Assault rifles dont require electricity to be made, even a lot of modern ones could be produced in an old fashioned steam engine driven machine shop. They will just take about twice as long and cost twice as much to make.
There are actually not many electrical components you couldn't replicate using pneumatics or hydraulics. The only area that might lead to problems is the capability of electricity to produce, emit and register light, heat or other radiation or trigger chemical processes. You could even build a pneumatic or steam-operated computer, accepting that it is going to be much bigger, clunkier and much more susceptible to mechanical wear than its electrical counterpart.
Some technologies like electrolytes that are typically used for metal plating or the production of metal alloys can be replaced with pure chemical processes, albeit at the cost of effort and time (you can produce Aluminium, for example, without electricity - See potassium reduction).
Weaponry as such is pretty simple technology - an assault rifle does not need electricity, neither for operation nor manufacturing. Even guidance systems for missiles and rockets can be purely mechanical (even based on clockwork technology, maybe, early torpedo guidance systems were purely mechanical), but might have some limitations on sensor technology and no obvious method for a remote control without a radio technology.
You would face a lot of problems that you wouldn't face when having electricity available, but keep in mind people normally don't miss things they don't even know they exist...
The fact that human technology was never forced to invent solutions that work around missing knowledge about electricity (which I, BTW find highly improbable, but that was not your question), doesn't mean that such workarounds do not exist.
I think it all depends on your scenario. Electricity exists by itself and it's known since 2700BC and Thales made experiments with electricity as early as 600BC, so in any case what you mean is "ways to create or manage electricity as we know it". Or do you mean ELECTRONICS?
Think about this: electronics needed for missile control require electric circuits. Do you know which other thing require (and has) electric circuits and impulses? Neural Networks. So, as you can see, you don't need a society to understand or manage electricity, it just exists inside us, even in animals. However, you need an understanding of the methods to manage it to create electronic components!
You also mention it could behave differently, so that allows us to think in scenarios where a society developed other methods. Maybe gravity, magnetism, fluidics, quantum chemistry, quantum computing, electrochemistry, advanced thermal energy, some kind of unknown physics, even magic, why not? Electronic devices use energy, so as long as you can create energy from some source, you'll be able to develop devices. It doesn't matter what kind of energy you create as long as it is enough to make the device work
Furthermore, I see fluidics was already mentioned, so here you have some uses of fluidics:
Fluidic injection is being researched for use in aircraft to control direction, in two ways: circulation control and thrust vectoring. In both, larger more complex mechanical parts are replaced by fluidic systems, in which larger forces in fluids are diverted by smaller jets or flows of fluid intermittently, to change the direction of vehicles. In circulation control, near the trailing edges of wings, aircraft flight control systems such as ailerons, elevators, elevons, flaps and flaperons are replaced by slots which emit fluid flows. In thrust vectoring, in jet engine nozzles, swiveling parts are replaced by slots which inject fluid flows into jets. Such systems divert thrust via fluid effects. Tests show that air forced into a jet engine exhaust stream can deflect thrust up to 15 degrees. In such uses, fluidics is desirable for lower: mass, cost (up to 50% less), drag (up to 15% less during use), inertia (for faster, stronger control response), complexity (mechanically simpler, fewer or no moving parts or surfaces, less maintenance), and radar cross section for stealth. This will likely be used in many unmanned aerial vehicles (UAVs), 6th generation fighter aircraft, and ships.
In short: quite honestly, your question has to be rephrased and you'll need to provide details about what level of scientific development did your society achieve. But as far as it goes, the answer is: YES, it's possible