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How do you make ammo after the world ends?
January 2, 2010 10:13 AM   Subscribe

How could you keep current guns supplied with ammo in a post-apocalyptic situation?

I understand that the shelf life of ammunition is not that long. In the books I read, Earth Abides and Summer of The Apocalypse, about 50 years after civilization had been erased, using guns was a matter of hit and miss, and not because of aiming, but because of misfires of old ammo.
I assume that with proper care, the guns themselves can be used for over a hundred years.
So, with this in mind, what kind of facilities would a pocket of survivors need to keep their cache of weapons (say handguns, sub machine guns, hunting rifles and maybe some .50s) well supplied with ammo. Let us assume they run out of pre-apocalypse cartridges or pre-apocalypse cartridges start misfiring? I know possibly the casing can be reused but what about the bullets themselves, the cordite and the percussion caps. What does it take to get those made, assuming they don't have the luxury of an up and running pre-apocalypse factory?
posted by spacefire to Technology (28 answers total) 9 users marked this as a favorite
 
In The Matrix Revolutions, they show a character grinding powder and making shells by hand (which volunteers were asked to do). So if you have the metal for casings somewhere (recycled or made anew) and enough powder, there's that option.
posted by cmgonzalez at 10:29 AM on January 2, 2010


Sorry, the problem is primers, not powder. And primers are high tech.

The answer to the original question is "You can't." Not in the long run.
posted by Chocolate Pickle at 10:30 AM on January 2, 2010


Gunpowder is only a few fairly readily-available components put together. The difficult part is refining it properly and in the correct mixture. That, combined with reusing shells and melting down your own bullets, which we used to do on the battlefield anyway, would be plausible.
posted by InsanePenguin at 10:33 AM on January 2, 2010


Ahh, of course. And primers. That would be hard, yeah.
posted by InsanePenguin at 10:34 AM on January 2, 2010


I'm not a gun enthusiast, but it sounds like the problem has been exaggerated in your books. Some quick googling results in lots of talk of using WWII era ammunition with only occasional misfires, and those being mainly confined to specific batches of ammunition. Assuming you randomly test fired a few rounds and stored your ammunition in the original cases it sounds like it will keep for many decades.
posted by ecurtz at 10:38 AM on January 2, 2010


50 years after the collapse of society, in order to support the production of modern ammunition, you would need a modern society. From the oil refiners that make the gas that runs the mining machinery that extracts the lead and copper for the bullets, and then runs the machinery that transports them to the smelter, who then transports them to the manufacturer, who buys powder from a company that gets its chemical energy from a modified Haber-Bosch process, which is dependent on access to the electrical grid etc...

Yes, one person could in theory do all these things, but the cost of a bullet would be enormous. A much better idea would be to take a look at the level of technology that remained in society and adapt the gun and its bullets to that level. There were guns in Medieval Europe, and their design reflected the practical level of technology at the time. Weapons technology is far from mechanically complex, a modern machine gun is mechanically less complex than some of the manufacturing machines that were around in the 1700s, but chemically it is beyond practicality.

I would propose that the limiting factor in the development of modern weapons has always been the level of chemical technology available to society at the time. Since those chemical resources would vaporize pretty quickly without society, you'd be better off with a matchlock and some crude black powder, than an M-16 and being left with spending 90% of your day making bullets for it.
posted by 517 at 10:39 AM on January 2, 2010 [4 favorites]


Bullet casting is really pretty straightforward and not that difficult, at least as long as you aren't trying to do jacketed bullets. Reloading is also trivial, there are numerous suppliers of all the necessary tools (balances/scales, presses, dies.) Spent brass casings with Boxer primers can be easily reloaded, but not polymer steel or brass with Berdan primers. The primers you would have to either stockpile or commandeer a factory, as I don't think that's a DIY job. It might be possible to manufacture your own smokeless powder in a DIY setting but I think that would be another thing you'd need to stockpile. (BTW, it's not cordite.) Certainly you could make a crude black power yourself but that would leave so much residue behind in the gun that it wouldn't be very useful.
posted by Rhomboid at 10:49 AM on January 2, 2010


Gunpowder is only a few fairly readily-available components put together.

What you're referring to as gunpower is really black powder and is not useful at all in modern firearms. Smokeless powder is much more complicated. This MSDS lists 14 ingredients, and the wikipedia page lists others. As that page points out, not only do the ingredients matter but also the shape/size of the grains is very important, so it's not just a matter of mixing to form a powder.
posted by Rhomboid at 11:13 AM on January 2, 2010


50 years after the collapse of society, in order to support the production of modern ammunition, you would need a modern society. From the oil refiners that make the gas that runs the mining machinery that extracts the lead and copper for the bullets, and then runs the machinery that transports them to the smelter, who then transports them to the manufacturer, who buys powder from a company that gets its chemical energy from a modified Haber-Bosch process, which is dependent on access to the electrical grid etc…

I don't think he wants to support a whole industry, or anything. This is a post-apocalyptic deal like in the movies, you just need to make enough ammunition for your small nomadic group to shoot somebody once in a while. You don't need to have mines, somebody could salvage the metal easily by just digging up landfills. You don't even need to process ore.

But yeah, I don't know how you'd come up with the chemical primers.
posted by floam at 11:14 AM on January 2, 2010


Mercury Fulminate percussion caps have been made since the early 19th century, would those work as primers for modern cartridges?
posted by spacefire at 11:27 AM on January 2, 2010


"You don't need to have mines, somebody could salvage the metal easily by just digging up landfills..."

Which would be a mine. The ore from which would have to be refined, if you wanted a bullet that shot straight. Although maybe you could go around salvaging car batteries for while.

I understand your point. I just think that people often underestimate the complexity of manufacturing processes. Like the the fact that the grains of explosive powder in modern 5.56 rounds that are fired by the m-16 are a specific shape. If they are a different shape, the gun misfires more often.

The jacketing process required to create a bullet would also be beyond what a person could do over a campfire in the dark of night, but maybe if they built themselves a little blast furnace...etc. The M-16 is designed to fire a jacketed bullet, so you would have to create a cast for un-jacketed rounds that matched the characteristics of a jacketed round if you wanted to hit anything at 50 yards. How many days would that take you to make, because the places that have casts for unjacketed 5.56 rounds are 1000 miles away from you because there is no demand for such a product right now.

There is no simple answer to the original question. Creating something like a primer that works dependably, goes way beyond my level of chemical knowledge, or even the level of most graduate students in chemistry if they didn't have access to the right tools and books. Creating one is also dependent on a huge amount of infrastructure that allows a person to have access to the things they need to make one. And that infrastructure always goes back to one of two places. The farmer's field or the miner's mine.

I think hollywood contaminates our thinking about the level of technology that would be available to a person if society started to fall apart. It's all very interdependent.
posted by 517 at 11:44 AM on January 2, 2010


Mercury Fulminate was created in a full-scale industrial society. The chemical industry that made it wouldn't exist in your post holocaust setting.

Making fulminate requires nitric acid. Making mercury fulminate requires mercury. Where do your road warriors get those things? Answer? From stockpiles left over from before the collapse.

But if you've got them doing that, you may as well have them getting finished ammunition from stockpiles left over from before the collapse.
posted by Chocolate Pickle at 11:47 AM on January 2, 2010


I agree with most of the others here; I don't think you'd be able to continue using modern repeating firearms. even percussion caps aren't something you're going to be able to make without a factory. You'd definitely be able to get results with a match/flintlock with black powder, though.
posted by ArgentCorvid at 11:56 AM on January 2, 2010


Old mercuric primers used potassium chlorate as an oxidizer which resulted in corrosion of the barrel because it was hygroscopic and not soluble in most bore cleaners, so you had to go through a tedious cleaning procedure or else the barrel would rust. They stopped making these after WWI and switched to a non-corrosive formulation based on lead styphnate. (link)

Another page mentions that mercuric primers weakens the brass too much to be reloaded after firing, so that would be another serious hindrance to the survivalist.

I was able to find instructions for making a lead azide based primer but it sounds extremely dangerous.
posted by Rhomboid at 12:02 PM on January 2, 2010


in any post apocalyptic situation the population is going to be reduced significantly and therefor the demand for bullets will also drop. thus any post apocalyptic world's bullet supply would be based on finding armories.
posted by Glibpaxman at 12:02 PM on January 2, 2010


in any post apocalyptic situation the population is going to be reduced significantly and therefor the demand for bullets will also drop.

I bet I would need more bullets in a post apocalyptic society than I do now.
posted by biffa at 12:19 PM on January 2, 2010 [2 favorites]


What if the original bullets were vacuum packed in steel cans with those little demoisturizer packets?

Wouldn't everyone switch to black powder/flintlock rifles? I wonder if a good archer would be more effective than a single-shot blackpowder rifle shooter.
posted by mecran01 at 12:27 PM on January 2, 2010


[After re-reading that link a little more carefully I see that I summarized it incorrectly but the gist of it is that mercuric primers were bad news for modern rifles.]

Keep in mind also that producing the primer compound itself is just part of the issue, you'd also have to manufacture and assemble the mechanical parts of the primer (cup and anvil) which most likely would require machine tools.
posted by Rhomboid at 12:39 PM on January 2, 2010


Vacuum-packing might be a reasonable solution. One could, if they found a large cache of ammo, could salvage one of those seal-a-meal vacuum sealers for food, power it with a gasoline generator, and store the ammo in plastic sealed containers for a very long time with relative safety. Most military ammo cases are watertight and airtight, but the air inside the container would still be problematic over time, depending on the humidity of the air inside.

As an aside, old dynamite is extremely dangerous. Over time, dynamite will "weep" or "sweat" its nitroglycerin, which can then pool in the bottom of the box or storage area. If the boxes aren't turned every now and then, it would become extremely unstable. What would look like a great find in a post apocalyptic world would just be a death trap. (The more you know...)
posted by chambers at 12:54 PM on January 2, 2010


After a couple decades, zip guns, bows, and crossbows would be the average ranged weapons. Although the technology to make reliable primers would be difficult, making exploding tips on arrows would not be.
posted by chambers at 12:57 PM on January 2, 2010


"I wonder if a good archer would be more effective than a single-shot blackpowder rifle shooter."

Depends on the effect you're looking for. A black powder rifle has a much higher muzzle velocity, and is more accurate at range, than a well-trained archer. Also, the amount of training required to be a decent shot with a rifle is much less than to be a decent shot with a bow.

The bow reloads much faster. If a score of you are looking to ambush a squad of enemies in the woods, the bow is your weapon. If you're expecting an engagement out in the open, the guys with rifles will kill off the archers before they can get close.

At least one British Army officer during the Napoleonic War proposed establishing some archery units. They would have been quite effective against advancing infantry, and they would have had substantial advantages during a downpour. As near as I can figure it, the two main reasons no European army did it were (a) archers have to be trained for years before they can even draw the 180-lb English war bow, whereas any idiot could be drilled with the musket; and (b) range.
posted by musofire at 1:00 PM on January 2, 2010 [1 favorite]


Plenty of folks load their own bullets. Probably these would also be the type of people to survive longest in an "end of the world" scenario. Their skills would be priceless and their own efforts of preparation are likely substantial. The equipment and skills would prevail throughout the years, I should think.
posted by carlh at 1:10 PM on January 2, 2010


The first thing I thought of was the "The Long Rifle" chapter in Little House in the Big Woods...
Sure its a little more archaic than modern weaponry but it has a nice description of what was required for maintenance...
posted by Redmond Cooper at 1:34 PM on January 2, 2010


Plenty of folks load their own bullets

That's not really the point because they buy all the components commercially -- powder, primers, bullets. Just about the only thing that is reused is the casing; they aren't really manufacturing anything, just assembling. The question is what happens when you can't mail order your primers and powder any more. Of course it is the case that reloaders will tend to have a much larger stockpile of supplies built up because reloading only saves money when you do it in bulk. But on the other hand the survivalist nuts that live in sheds in Montana and Idaho and whatnot have massive built-up stores of commercial 5.56 cartridges so it's also not necessarily true that the reloaders would be the ones who would last the longest.
posted by Rhomboid at 1:52 PM on January 2, 2010 [1 favorite]


As an aside, old dynamite is extremely dangerous. Over time, dynamite will "weep" or "sweat" its nitroglycerin, which can then pool in the bottom of the box or storage area.

That's true, but almost no one uses true dynamite any longer. These days if you see someone using red cardboard tubes to set up to destroy something, they're using ANFO. Which is cheaper, safer to produce, has more explosive yield, and if it sweats all it's sweating is fuel oil.
posted by Chocolate Pickle at 2:15 PM on January 2, 2010


I am thinking crossbows would be the weapon of choice once the zombie apocalypse is in full swing. You don't have to train for as long as you would with a regular bow, you could use modern crossbows, they are relatively silent, can be carried easily, etc.
posted by charlesv at 2:20 PM on January 2, 2010


I don't know the science of it, but it would seem to me that the answer is to figure out what makes the bullets go bad and find a way to fix that. My guess would be that the components eventually react when stored mixed together. So just horde an ass-load of the components and mix as necessary.

Or get good with a slingshot.
posted by gjc at 5:19 PM on January 2, 2010


FWIW, I've shot 30-06 ammo from WWI without any misfires. My buddy has used primers that were over 20 years old.

Any recently produced ammo, stored properly, will outlast you.
posted by IronSurfer at 11:43 PM on January 2, 2010


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