What forms of ammunition/munitions could people realistically manufacture or recycle when modern infrastructure and society is collapsing?

Question

The context: a big (fictitious) US Army base like Fort Hood or Fort Bragg is a focal point for civilisation hanging on as the apocalypse slowly happens around them. Over a period of several years, the world has gone to hell in a handbasket, infrastructure has crumbled, the economy has collapsed, law and order vanished in many places. What’s left of the US government is hiding under Cheyenne Mountain.

Among the causes of this economic and social collapse are:

• A multiple year drought, all across the Midwest.
• One of the Azores Islands rips itself to bits, causing a mega-tsunami which hits all along the Eastern seaboard of the Americas.
• A few months later chunks of California ‘fall into the sea’ in a series of mega-quakes.
• ‘Super-measles’ pandemic with a 30% mortality rate has swept across the planet.
• There are gangs of ‘mutant’ humans on the go. Some are no different to any other post-apocalypse bunch of bandits with guns, but other gangs are intent on killing off as many ‘normal’ humans as possible.
• One ‘kill the normals’ faction is slowly building itself into an actual army, and starting to take territory and hold it, rather than just looting and pillaging in Mad Max biker gang fashion. (That faction has their beady eye on my Army base and has put it on their To Do list).
• The advantage the mutants have is some ‘Jedi mind powers’ (These are not the droids you are looking for) and being physically stronger than humans. If they get up close and personal in a fight, you are toast.
• The advantage the humans have is more manpower, being properly trained in warfare, and owning lots and lots of weaponry specifically designed to stop the enemy getting up close and personal – everything from handguns to artillery. However, all that firepower requires munitions, their stockpiles are getting low, and there are no factories manufacturing it any more... (Or at least none anywhere that my guys can get deliveries from).

After several years of this chaos my army base and garrison town has (accidentally rather than intentionally on their part) evolved into a ‘city state’: an island of civilisation, defending itself and a large chunk of farmland from marauders – both normal human and mutant human ones.

So what munitions can they feasibly recycle or manufacture as their stockpiles start to dwindle? Can they just make blasting caps and refill brass for small arms? What about a 50 cal? Are the artillery guys and tankers going to become unemployed due to lack of shells? (I suspect a ‘home made’ tank shell is a very bad idea, but have no actual facts to back this up). Also, what raw materials are they likely to start running out of?

In terms of the tech and resources they have available:

1. Electricity is not a problem. They have a power station on their doorstep and the know-how to keep it running. (Until the bad guys take it out).
2. Manpower is not a problem to start with. Though as things progress, (1) their population will take several hits from disease etc and (2) producing food will become more labour intensive so they’ll need to dedicate more folk to farming.
3. The local town can have whatever light engineering facilities I want to invent, but it I don’t want them mining for resources. Recycling spent brass is fine, but smelting ores to make more from scratch is not.
4. Fuel and mineral oil lubricants ARE a problem. Many vehicles are being converted to run on alcohol. Anything too big or too heavy to do this has effectively become scrap metal. (Bye bye tanks and aircraft).
5. They are doing cost-benefit analyses on what crops they grow. For instance if they grow rapeseed, they have to decide what proportions they feed to people, feed to poultry to get the eggs/meat, use as lubricant or convert into biodiesel/ethanol for fuel.
6. They are in contact with other military and government places by radio, so any “we tried that and it didn’t work” or “our expert suggests this” ideas can be traded back and forth.

Answer 1

Rifles and handguns and even larger equipment can only be kept in working order as long as there are parts and refills for them. If there are no stores left then other options need to be sought rather than keeping the items working in their current form.

The answer to “what they can produce to resupply themselves” depends both on how much they have in the ways of stores and supplies. Eventually they will run out though; their modern materials depend on a huge infrastructure to produce which simply isn’t there anymore in your scenerio. Reloading the brass isn’t the issue, there’s more than likely one or two people in that area that privately own reloading stations or equipment, to say nothing of what the military base might have. The problem is what do you do when you run out of modern powder or caps? Brass can be reused, but eventually will be come damaged and needs replacement as well. You simply can not make the majority of what you would need without very specialized equipment and resources.

An alternative questions is; what do they replace their current firearms with? The crossbow (suggested by Thucydides) and other mid-eval implements can be a good option if nothing else is avaiable, but if you have access to all the natural materials to make old-fashioned gun powder then you can “easily” make fire arms that work with it (with modern knowledge and tools). Heck, I bet you can even remember the recipe for doing it if you think on it for a little bit... and you can even make cannons! taking it a step further primitive blasting caps can be made as well with some middling chemistry (fulminate of mercury?), and you can even design and use “wood” casings for shells. It all becomes very "civil-war".

If you want to get creative, flame throwers using metal plumbing and grass/potato alcohol are another thing that could be made, but I'm not sure how many sane soldiers would actually want to use one in combat.

An interim solution being that one can even refill brass with old style gunpowder and use it with modern fire arms( if you’re fairly desperate), but it’s going to foul a weapon pretty quick, and you still have the problems of the weapons themselves breaking down over time and use.

Any sort of “nation-state” that’s going to last against constant external pressure is going to need resources it can find or produce reliably to support its defense and create and maintain its weapons, or one day they will simply run out and the next group of rabid dogs that come across them will have a field day.

Answer 2

Can I suggest a real place for this? Rock Island Arsenal is an actual munitions plant, on an island in a river, with a town. That makes many things simpler: they can make new bullets, cases, and so on until they run out of supplies. There are quite a few supplies required:

1. Brass, for cases and bullet jackets (different alloys)
2. Lead, usually in the firm of wire, for filling bullets.
3. Powder, which needs quite a high standard of industrial chemistry to make to a good standard, and isn't usually made at arsenals.
4. Primers, which also need a good standard of chemistry. The compounds are quite dangerous to handle in bulk, because they're shock- and friction-sensitive explosives. They are sometimes made in arsenals.

Answer 3

In that situation people would almost have to return to older tech.

Shotguns and some rifles, especially breach loaders like double-barrel and over unders could be easily refitted to fire self-contained black powder shells and cartridges. Projectiles from a smooth bore shotgun barrel could be simple shot or slugs made from lead, copper, or steal. While not as powerful as modern shells and lacking the accuracy of rifled barrels, it's better than nothing and making ammo would be relatively easy. (There are YT channels dedicated to shooting weird stuff from 12gg shotguns like play dough, which cracked a cinder block.) But a strict cleaning regimen would have to be enforced to prevent fouling. Rifle slugs would have to be more precisely made and the weapons cleaned more often. Larger calibers would be preferred so the projectile's mass could compensate for the lower velocity from black powder when it comes to causing damage to a foe. Shells for rifles and shotguns would be best made of brass so they could be saved by the soldier to be cleaned and reloaded by the armorer or another specialist. They would eventually wear out, but the lower pressure of black powder ignition would afford them a longer lifespan. After they're "shot out", just smelt them back into shells or something else. Both shotgun shells and rifle cartridges would require primers with mercury fulminate. This would require someone with chemical knowledge. But it's not that difficult. "Pop Its" those white little bags of paper kids throw on the ground have trace amounts of fulminated mercury.

For artillery, a combination of torsion powered, counter-weight thrown and black powder cannons would be a good solution. Whereas the cannons can fire a few types of ordinance, ball, shot, chain, canister/grape-shot, explisive etc, each with a specific purpose in combat and pre-made Trebuchets and catapults can hurl almost anything from rocks, bricks, pots of burning pitch, carcasses, etc. Some ammo can be designed for specific purposes, but many things can be used in a pinch. (Though the same holds true for cannons, especially at close range where accuracy isn't as critical, i.e. load that baby up with gravel and dinnerware!) The artillery would have to coordinate their actions in order to capitalize on the different strengths and weaknesses of each piece. Then of course there's bows, crossbows etc. All of which other poster have mentioned.

As for your question about tanks. Most modern tank guns, like the Abrahms use a smooth-bore and are breach loaded. So with some engineering refits and trial and error, (150mm howitzers could be used to practice on, same caliber), a self-contained black powder shell could be designed and pressed into combat. It would be limited in range by the lower pressure of course. But my suggestion would be shot for anti-personnel, turning the gun into a big shotgun, (imagine tank crews having to get close and personal before blasting away with a tree trunk thick shotgun?), or incendiary using phosphorus. But conical and even fin-stabilized sabots could be designed. Any shell type would require a STRICT cleaning regimen and the phosphorus should only be used in a emergency since damage to the barrel is more likely. Also a flush/purge sytem that can be operated from within the cabin would have to be implemented to clear out any unburnt or hot powder that could set off a shell prematurely. A compressed nitrogen sytem would work well or a fire extinguisher directed into the breach in a pinch. These same concepts can be used for artillety like howiters. Other ideas: black powder cartridge firing crank driven gatlings. Mortars. Grenade launchers/lobbers. Primitive rockets. Also using hydraulics and pneumatics to crank or re-set catapults, trebuchets, or ballista, thus increasing their rate of fire.

Hope this helps.

Answer 4

Given the difficulty of making modern weapons without modern infrastructure, one quick and dirty recycled weapon will be crossbows and ballista.

The power of a crossbow is in the tension of the bow, and truck leaf springs can provide a pretty powerful bow, so powerful, in fact, that a normal human will not be able to draw it by hand. In the Middle Ages, a steel crossbow was wound using a mechanical ratchet, which can also be easily made or even adapted (volleyball nets are tensioned using a ratchet mechanism, for example).

You will have a slow rate of fire, but a crossbow bolt fired from such a weapon will penetrate virtually any practical armour, and at a fairly long range as well.

Crossbows were one of the leading weapons of the "Infantry Revolution" of the 1400's, since they did not require a lot of training to use effectively, allowing even a mass of relatively untrained men to prevail over knights who needed a lifetime of training to be effective.

Answer 5

Gunpowder is fairly easy given your situation but it will be fairly low quality and kind of inconsistent, so maybe retrograde your weapon systems to match. Crossbows, long-bows, and muzzle loading weapons go to your infantry/riflemen. Yes, you get lower rates of fire, but you gain reliability for things that may fall prey to inconsistent quality. You could add primitive clay pot grenades to this arsenal. Teach your kids to use a simple sling (like david and goliath). get them up high, and those falling rocks will encourage the enemy to move slow.

Balistae, trebuchets, and re-fitted howitzers and tanks to act as really big shotguns will act as your artillery. To the artillery you could also add the Hwacha from Korea. Move your tanks out to strategic positions and focus maintenance efforts on the gun and turret. You ain't going to be able to rely on the mobility because they require way too much fuel. that fuel would be better used in earth movers to create fortifications. Fecal matter smeared caltrops on the approaches that you created by your smart use of earth movers will slow your enemy out there even more than rock slinging kids.

I am imagining this taking place near Fort Bliss near El Paso Texas. The hills around there could really help in situating you in naturally fortified places.

You are talking about a situation of diminishing resources and the replacements will not be uniformly reliable, so you want to guard against it while looking forward. Utilize what you can, for as long as you can, but be ready to fall back to something else and make that transition as smooth as possible. That should help your Proto civilization survive the longest.