This is probably a general question, although it’s related to a role-playing game I and some others are setting up. It’s set in your average post-apocalyptic future, and we’re currently debating about firearms ammo.
The question is, if you can manufacture (not reload, manufacture) cartridges adequate for revolvers and bolt-action rifles, do you then have to concede that cartridges for semi- and full-auto are feasible? Or is it plausible that your production facilities remain just primitive enough that too many rounds fail for automatics to be practical? I favor the latter, since given the scenerio even semi-autos would give our PCs near-overwhelming firepower, and the limitations of less advanced firearms would make it more interesting. On the other hand, it seems like historically once cordite and other propellents replaced black powder, the first semiautomatics were developed only a few years later. So how much more exacting are cartridges for automatics vs. manual feed guns?
Someone with more knowledge will come in shortly, but semiautos can be more picky than bolt-action rifles. 7.62x54mmR comes in light ball for rifles and heavy ball for machine guns. The Mosin Nagant bolt-action rifle should shoot both, and the ballistics will be much different but both will still work. However I hear dire warnings about using heavy ball in the semiauto SVD (“Dragunov”) rifle.
If you’re talking about making them from raw materials then deep drawing brass cartridge cases is not something people learn by watching Sesame Street. Breech-loading firearms didn’t really become feasible until mass production of solid-drawn cases that would work reliably was perfected.
Well, if your semi-auto fails to cycle, you can just cycle it manually using cocking handle. Even with really atrociously inconsistent ammo that works 50/50 it’s still twice as good than always reloading manually.
But the bottom line is it depends. What kind of weapon and what kind of ammo. If you are using AR-15 clone then substandard, impure propellant can cause serious damage in short time. On the other hand simple blowback-operated weapon with loose tolerances will work even with really badly manufactured ammo.
Granted, being able to make a primer for a revolver or rifle cartridge would carry over to semi and full auto weapons, the chemistry and quality control on just that task would be a major project.
You stipulation for the game would be supportable. We, the US Army, currently have ammunition manufactured for one machine gun that isn’t high enough grade for use in a more rapid firing gun. And that’s with our current technology. [One example is 7.62mm linked for the M60/M240 machine gun that is not suitable for use in the M134 Mini gun. Standard linked ammo is not reliable enough at the higher rate of fire].
A second argument is that the rate of production in a less advanced environment would not keep up with the higher rate of consumption of an automatic weapon. You can make enough to support point and aim fire but not spray and pray.
Blackpowder cartridges were around for a while before smokeless powder made the scene. Blackpowder creates enough fouling that autoloaders that use blackpowder cartridges are impractical.
The easy solution, therefore, to your problem is to have the firearms technology at around a mid-1870’s level.
You could probably compromise, and end up with some interesting game mechanics. I.e., while the everyday bandits might be carrying revolvers with appropriate ammunition, there could be some rare semiauto weapons floating around out there (perhaps in Ancient Military Underground Caches). Quality ammunition for these would also be rare. That way, the group would be forced to use more mundane weapons for everyday encounters, but they could hoard and collect high quality munitions to use during tough fights.
If you wanted, you could even give the option of using the crappy ammo in their precious AK. Of course, that would lead to high rates of misfires, jams, wear and tear, etc.
FWIW, I’ve fired off an old block of .22LR my dad had laying around from 20+ years ago. It was just fine in a bolt-action rifle, but it wouldn’t reliably cycle in anything semiautomatic. Every third or fourth round would cause some sort of jam (excuse my imprecise terminology here).
How, exactly, are they manufacturing their cases? Are they turning them individually on a lathe? That, right there, gives you a way to limit ammo production, if so. If they are coining them i.e. drawing them, where are they getting their stocks of brass? Once again, a way to limit their production.
What are they using as a priming compound? Mercury fulminate? Lead styphinate? Where are they getting the raw materials for this? Priming compounds are also kind of dangerous to manufacture and handle.
Blackpowder is significantly easier to make than smokeless powder. It generates lower pressures, and therefore the guns don’t require as sophisticated a level of metalurgy as smokeless guns.
If they are sophisticated enough to be manufacturing metallic cartridges from scratch, then they are sophisticated enough to be manufacturing guns to use the cartridges. If you can make pistol cartridges in quantity, then you can make a basic blowback SMG to fire them.
If you want to have guns in the campaign, I think you’re either going to have to have the characters scavenge ammunition or come up with some creative ways to limit their ammo production.
First models of Maxim machine gun were chambered for blackpowder .45 ammo. You can have friggin’ blackpowder hmg. Maybe not as reliable as one using smokeless ammo, but if I had to choose between machine gun and revolver, I know what I’d choose.
In what way was the black-powder Maxim impractical? I’m sure there were issues with smoke obscuration and whatnot, but as far as I am aware the Maxim design worked well enough irrespective of the propellant used. Bugger-all use as a personal weapon, certainly, but for defending a train or building from the zombie hordes it would be pretty useful.
Note that I used the term autoloader. In the US, that term typically refers to a semi-automatic weapon. It is used to describe shotguns, rifles, and pistols. If I had meant machineguns like the Maxim, I’d have said machineguns. I got the impression that the OP was concerned with hand-held weapons as well, rather than tripod-mounted heavy machineguns. I stand by what I originally said. Blackpowder autoloaders are impractical due to fouling issues. During the transitional period from blackpowder to smokeless powder, the gun companies invented whole new cartridges that were smokeless-only for use in the newfangled autoloaders. The .22 Winchester Auto is an example. There were cartridges that were available in either smokeless or blackpowder loadings; the blackpowder versions didn’t work very well or very long in autoloaders.
As for blackpowder machineguns, there were some. Blackpowder, however, fouls so heavily that stoppages happen much, much more quickly than with a smokeless propellant-using weapon. Also, though it may sound silly, you’d have to deal with the machinegunners very quickly being surrounded by a very visible cloud of blackpowder smoke. This would have the twin drawbacks of simultaneously giving away their position and obscuring their view.
Historically, machineguns didn’t come into their own until smokeless powder was invented.
Good questions, especially what primer compounds can plausibly be produced. Currently we’re leaning towards the following compromise: ammo (chiefly what primer is used, such as fulminate, potassium perchlorate, or lead azide) comes in lousy-but-plentiful vs. good-but-expensive. Auto-loaders are available but are considered too unreliable and expensive for general issue; a handful of affeciandos use them but most people prefer the simpler hardier weapons. Our Heroes will be using smokeless powder although they may occasionally run into people using black powder muskets.
When J M Browning invented his 1st Auto-Loading shotgun this gun would continue to fire until there were no more shells. The gas operator lever was also connected to the trigger mechanism.
There are pictures in the “biography of John Moses Browning”
But as far as manufacturing ammunition, I would be a proponent for a manual repeater. when supply is questionable, I would not be waistful.
There is much to be said about quality of ammo for simi’s.