Which common military equipment could last 500+ years after an apocalypse?

Question

So I’m writing a story set 500 years after a nuclear holocaust. In the scarred, charred wastelands of the former United States of America, a beacon of light, a humanitarian, righteous organization exist. They are known as The Snipers.

History

The Snipers are(mostly) the descendants of military personnel stationed at a base in New Mexico, back in the 21st century. When the nuclear war happened, they were, for some reason, not hit with any nukes. The soldiers stationed their, from the safety of their base, saw the violence and horrors of the post nuclear world firsthand.

The commander of the base, a man by the name of Taylor, lead his group of soldiers pit of the base to start fighting of the marauders and cannibals, and soon successfully brought order back to the city of Albuquerque. The soldiers found their wives and children, and some men were sent on an expedition to another nearby military base to retrieve any left behind weapons and armor. The Snipers devot themselves to bringing order back to the wasteland, and any person who wants to can join the organization.

26th century

The Snipers are know the sworn defenders of the Wasteland, and often use their knowledge of military strategy and access to weaponry to fight of wrong doers. Which brings me to something. After the apocalypse, most people have been knocked back it pre-industrial technology, and factories the manufacturer replacement parts for weapons are piles of rubble now. The Snipers have knowledge of how military weapons work, more than anyone else, but they still live in a post apocalyptic world. They can only scavenge parts or diy something on the spot.

So, my question is: what common modern military equipment can survive 500+ years of continual use without becoming permanently unusable?

• Tanks, keeps and helicopters don’t last, as it is integral to my plot that they don’t

• Ammunition is not a problem, as they know how it make gunpowder and shells, thanks to some diagrams they have

• They have detailed knowledge of the schematics and maintenance needed of their weapons, it’s just that they can only provide the bare minimum of care needed

Answer 1

what common modern military equipment can survive 500+ years of continual use without becoming permanently unusable?

Books.

It's been 500 years since the nuclear apocalypse. People spend their days thinking about where their next meal will coming from and whether little Napho'ug is going to die of cholera. A group of bandits rolls in with arson, rape, and murder on their mind. All hope seems lost! But the bandits have made a terrible mistake: They've entered Sniper territory.

• The bandit guards posted around the perimeter of town just...disappear (Field Manual 21-150: Sentry Removal)
• Snipers have the ability to appear out of thin air, attack, and vanish at will (21-75: Cover, Concealment, and Camouflage)
• They speak without sound in their own battle language... (21-60: Arm-and-hand signals)
• ...defeat even the greatest bandit warriors... (25-150: Hand-to-hand combatives)
• ...and survive wounds which would kill any Wasteland dweller (21-11: First Aid)
• The bandit force finally breaks and runs when a messenger arrives from their home base with news that their leader has been found dead in his bed (31-20: Infiltration and Exfiltration)

"There are no dangerous weapons, there are only dangerous men." - Robert Heinlein

The Snipers are dangerous because they know what everyone else has forgotten: how to fight like an army, not a mob.

and

Answer 2

what common modern military equipment can survive 500+ years of continual use without becoming permanently unusable?

The only military equipment that can last unused 500 years is stone equipment: axes and arrow tips, oxidian blades and such.

Continuous usage would wear anything out in few years at best.

Unless the weapon is a bare throwing stone.

Answer 3

No standard infantry equipment will survive "continuous use" for 500 years. For example, the barrel life of the M4 rifle is advertised as 10,000 rounds. Even if combat is infrequent, merely conducting regular training of new soldiers and zeroing practices will wear a rifle out to the extent it requires a factory rebuild in a few years, a decade at most. Boots, load-carrying equipment and other "worn" items will last a year or less.

Fuel, ammunitions and explosives will not last. Petrol (gasoline) will only last a couple of years without stabilisers, diesel will last a maximum of 15 years, small arms ammunition stored properly will last for decades but not centuries. So ammunition definitely needs to be manufactured as per your question, and all vehicles will be out of action within less than two decades unless fuel is being currently produced. It will be a race to see whether fuel runs out before spare parts run out for vehicles.

Properly stored equipment, however, may last for a long time. For example, I was still occasionally in the 1990s firing a .303 Short Magazine Lee Enfield manufactured in 1917. The rifle was certainly not in continuous use for the intervening 80 years though. I have no difficulty believing that the metal parts of a rifle stored in grease could last for a long time, although the stock (plastic or wood) may need to be replaced. 500 years is probably too long though - the same chemical processes that make fuel degrade would also affect packing grease I suspect.

The short version is - nothing will last through even low-frequency continuous use for even decades without needing factory-rebuild type support. In 500 years society needs to have rebuilt its infrastructure or nothing will be left that is not preserved in a museum - but if the infrastructure cannot be rebuilt in even 100 years then it will probably never be rebuilt.

Answer 4

So, my question is: what common modern military equipment can survive 500+ years of continual use without becoming permanently unusable [with repairs only at pre-industrial level]?

First point, you’re really making it hard for yourself by going for 500 years. For all but a handful of very durable materials, that is an extremely long time for anything to survive, and it doesn’t seem necessary for your plot. Not much actually useful stuff will survive that long. For example, as KerrAvon notes, if they are actually in “continual use” then after a lot less than 500 years, even bolt-action rifles will be completely shot-out. You can appreciably increase the list by reducing the time span. At 100 years, for example, there will be no people living who knew life before the collapse, but many carefully husbanded machines could still be operable. For example, there are plenty of examples of rifles a little over 100 years old that are still usable (if a long way from top condition), and even a few, rare examples of 100 year old motor vehicles that still work.

“Usable” is a little vague – I will assume you mean “usable for its original purpose or something close to it”, since otherwise, you can assume that all metals (and some other materials, like glass) will be reused and recycled indefinitely, just as has happened for most of the past 5,000 years.

“Pre-industrial” is also pretty vague. In terms of machine maintenance, there is a world of difference between a) a simple agrarian society where the artisans don’t know even the general principles behind engines; versus b) a developing nation where mechanics don’t have access to the best tools and parts but have a pretty good idea how to keep machinery running as long as possible with what they have. For example, in the real world there are developing nations that still have early Cold War armoured vehicles in their fleets. Most of the vehicles have been scrapped, and the remainder kept running by cannibalising the rest, but some 60 – 70 year old armoured vehicles are still in service. Immediately post-collapse, your society will be much more like b) than a). How it evolves over time is a difficult thing to predict; they may gradually recover tech, or gradually lose it. But by 500 years later, whatever direction the change goes, it is likely to be pretty extreme. Consider the Fall of Rome: in 500 years Europe went from a fairly advanced society, to the barbarism of the early Dark Ages, and then recovered to the High Middle Ages -- a very, very different society to Rome.

Anyway, I did a little brain storming, and here’s a few specific examples of things that might still be usable after 500 years of use:

• Body armour inserts: modern military body armour consists of a mixture of high strength polymer cloth with critical points reinforced with inserts usually made from super ceramics. The polymers will not last anything like 500 years – apart from anything else, they are slightly weakened every time they are exposed to sunlight. However the ceramic plates are close to indestructible. They can be cracked by intense impacts (such as bullet strikes), or destroyed by extremely hot, sustained fires. Otherwise they will last not 500 years but more like 50,000. How people actually use them when the rest of the armour is gone, is up to your imagination.
• Identity discs (dog tags): deliberately designed to last an extremely long time, and can probably survive for millennia. They would not have the bearer’s name but that of a long-dead ancestor. However to take an analogy from Dark Ages warriors after the Fall of Rome, they might be seen as a badge of honourable descent from an ancient hero. Of course one part of the set is supposed to be left in the tomb of the hero, so the descendants would have only the graves registry part. It might be an interesting episode to discover an ancient tomb and find that your silvery tag of hardest mithril matches that of the long dead hero!
• Stainless steel razor wire: Normal razor wire is either all carbon steel, or carbon steel core with a stainless tape. Either of these would have rusted to pieces in 500 years, unless installed somewhere very arid. However there is also a grade rated for marine exposure which is stainless throughout, and in any non-marine environment it should be usable for centuries.
• Bayonets: utility knives will be worn out from re-sharpening, but maybe not bayonets. For bayonets, continual use means daily wear, not daily stabbings. In units where bayonets are not to be used as utility knives, a bayonet only needs sharpening once every few years. In that case it may last centuries, provided it is kept dry and occasionally oiled. (However it isn't clear that a 21st century bayonet would actually be more useful than a polearm purpose-built from other recycled steel.)
• M1 steel helmets: I don’t know how long the new polymer based ACH and LWH helmets will last, but they will most likely deteriorate much like soft body armour. However the old school M1 is made from high manganese Hadfield alloy. That is not quite as corrosion resistant as stainless, but is much better than mild steel. With modest care it could remain serviceable for centuries.
• (Parts of) Load bearing equipment: the modern polymer based stuff again will not last. It is treated to resist the effects of sunlight and could survive for a century or so if the stitching is occasionally repaired, but 500 years seems dubious. Ironically, it is once again the old-school stuff that will last better. It is made of canvas and chemically dulled brass. The canvas is chemically treated to make it very resistant to rotting, but it probably isn’t resistant enough to last 500 years. However the brass fittings will last for millennia, not centuries. If the fabric parts are replaced by leather or new cloth whenever they wear out, you could end up with a hybrid LBE designed to the new user’s needs, but incorporating old parts. Still, the effort here may not be worthwhile.
• Optics: many optical devices are made of imperishable materials and have no working parts as such. It is quite possible for these to remain useful more or less indefinitely, provided they are kept reverentially so they are not broken or scratched. This may include field glasses (binoculars) and some types of rifle scopes. Of course, once you let the lenses get scratched it is ruined.
• TNT: Most explosives are not very stable and can be stored at most a few decades, usually less. High purity grades of TNT are very much more stable, and it is not totally out of the question that it could last 500 years if stored in a continuously cold place such as a cave. (A bit of a guess, as no-one has ever tried that, but there do already exist samples over 100 years old which seem to be doing fine.) Detonators are a different question: they will not last anything like that long, so new ones will need to be made, and that isn’t simple.

• White phosphorus:WP is a pure element and will last forever if protected from reacting with the external environment. There's the problem: after decades, never mind hundreds of years, some of the munitions holding the WP start to leak. Not a pretty look in the middle of a magazine! However you could argue that in a professional storage site, this should not set fire to the rest, and a reasonably large fraction may still hold WP. Another issue is that most WP munitions also have a small explosive "burster charge" which will certainly have deteriorated, however not all munitions are stored "fuzed" with this charge in them. Getting the WP out and using it is another substantial challenge (quest?!) for Dark Ages warriors, or perhaps apprentice mages in this case!

• Tungsten penetrators: armour-piercing ammunition contains a super-hard core, or "penetrator", which is typically made from tungsten heavy alloy or tungsten carbide. Your 26th century Dark Ages warriors may not be able to launch these from a firearm, but they could be re-purposed as the tips of crossbow bolts.

• Radium dials: the tritium light sources used in some modern military equipment has a half-life of 12 years, hence a practical life of only 6 or 7 years between recharges. In contrast the (much more dangerous) radium paint used on some World War 2 equipment has a half-life of 1,600 years and will still be glowing brightly in your timeline.

• Pan, set, messing and KFS: The mess pans are made of a lightweight aluminium based alloy that is very resistant to corrosion. They can be melted if allowed to boil dry, and will eventually just wear out as the soft metal is scraped by harder utensils. However I have a set that was made during the Vietnam War and is still going strong. I would guess that with reasonable care, a significant fraction of them would be usable for at least a few centuries unless it was desired to recycle the metal for something more valuable. As for the KFS (knife, fork, spoon set), they are a tough grade of stainless steel and will last for millennia rather than centuries. (In practice the biggest problem is losing part of it, after which the rest doesn’t lock together properly and it becomes easier to lose that also.)

Ammunition is not a problem, as they know how it make gunpowder and shells, thanks to some diagrams they have

This is considerably more complicated than most folks seem to realise. Modern high performance rifle cartridges operate very close to the pressure limit of the steel, and are used to provide extreme accuracy (especially for snipers.) In other words, to make them simultaneously safe, high performance, accurate, and reliable is a high precision application for explosives: a careful balancing act between multiple processes. It isn’t a matter of following some internet recipe for nitrocellulose; powder making is way, way more complicated than that.

The process involves chemical solvents, precise quantities of various additives, and repeated chemical and physical testing. Quite minute amounts of batch-to-batch variation can result in greatly degraded accuracy, or even blowing up your gun. Slightly larger batch errors can produce very low performance (including low or inconsistent velocity at the same time as dangerously high pressures), misfires, hangfires, increased muzzle flash, and heavy gas system fouling that stops the weapon from cycling. It can even result in unstable powder that bursts into flame spontaneously and blows up your ammunition stores.

While it is plausible that your survivors could, with difficulty, make black powder for muzzle loaders, it is extremely unlikely that they could make smokeless powders for modern military rifles.

Answer 5

There is 500-year-old military equipment around. It is found in various museums and similar collections.

• Metal may last if it is properly cared for. But if blades are frequently sharpened, they might have been whittled down to nothing.
• Wood may also last. I'm not sure if a 500-year-old wooden shaft could still take the strain.
• There is no data for plastics yet, but I'd bet against it. Plastics contain plasticizers which may be lost over the years.
• Electronics will be gone.

So the blades of bayonets or the barrels of rifles may be still around, but with new-made wooden grips.

Answer 6

I would think big and static. Fortresses, tank barriers, bunkers, moats, etc, should be able to last for hundreds of years without requiring highly specialized knowledge. Some care will be required, but it'll be minimal.

Answer 7

There are two current items that I'm aware of, though only one is officially issued.

1. The rock. This is a staple of the street rebel and bored soldier. Rebels throw them at soldiers and bored soldiers throw them at just about anything. Mostly they're considerably older than 500 years on first use.

2. The concrete sandbag. Instead of filling the bag with sand, they can be filled with concrete mix before use. While not far off the same concept as rocks, these do have regular purpose when building structures that need to last longer than standard sandbags will allow.

Answer 8

1) add 'icy, radioactive' to 'charred wastelands'. Effects of nuclear war will go far beyond the cooking & blasting, especially in the Northern America, THE primary target of a full-scale nuclear strike.

2) after 500 years, if by some luck there is still some human alive in the whole world, they would not be living in the northern America where there would be no food and useful water.

3) Any survived residual warfare technology would consist of...nothing. Without even the slightest maintenance such as regular cleaning, in 500 years of rains and ice and dust there would be not even a useful knife, even less a musket.

4) it doesn't matter if the base in New Mexico is hit or not during the war: without central distribution of food, without a power plant of their own, with the land all around dead as it can be, the people trapped inside would be long dead before 500 years passed.

5) there would be no population to rescue, no government to refer to -heck, in 500 years the 2018 English language would have changed completely together with the economic and political system

6) they wouldn't have the basic resources to forge elaborate weapons. With industry completely collapsed and gone, the best they could do would be to melt metal scraps to fabricate rudimental guns charged with metal pellets instead of bullets, and bronze cannons