Ammo life span

fyrefyghter33

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I was wondering how long ammunition stored in a cave in the mountains would last.

It would be modern day ammo and it would be located in the Pacific Northwest of the US.

Thank you in advance for your answers
 

Cella

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What kind of containers is it housed in?
 

fyrefyghter33

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Sorry that would help wouldn't it. It would be a cache of military ammo. For rifles mostly with some side arm ammo as well. Would calibre make a difference?
 

Cella

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Well, from what I think I know, if the temperature is kept constant (like it would be in a cave) it would stay relatively stable, so long as there wasn't much moisture to corrode the metals.

How long do you need it to be kept good for? Like, 30-40 years, or a few hundred? Given that the technology of the guns still requires the same ammo at a later date, I'd think somewhere between the 20-40 year mark could be believable.

There are more weapon savvy people on the board though who might and should correct me if'n I'm mistaken :)
 

snafu1056

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Based on some quick research, your best bet is a stable, room temperature, low humidity environment. Extreme heat, extreme fluctuations in temperature, and humidity and moisture are the biggest ammo killers. Well-stored modern ammo can last for a minimum of 10 years, probably even several decades.
 

ironmikezero

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benbenberi

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They sometimes still find WW I leftovers that are live and dangerous. WW II-vintage stuff even more so.
 

badwolf.usmc

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It depends on how it is stored, the storage container and packaging, conditions in which it is stored, and the type of ammunition that is being stored.

Modern day ammo, if kept cool and dry and in the original packaging, could last for decades, if not longer.

However, caves are not known for being dry, and if you have ammo just tossed into a cave then it isn't going to last that long. You need to have a sealed room that keeps out the elements.
 

MaryMumsy

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As a matter of personal curiosity, would the same apply to shotgun shells?

My Dad's shotgun is loaded with probably 40 year old shells. And there are spares. I've considered taking it to one of the gun shops that have shooting ranges and instructions, to have them unload it for me.

MM
 

Trebor1415

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Modern military ammo actually has a somewhat shorter lifespan than World War II era military ammo. Back in World War the chemicals used in the primers were corrosive to the bore if the weapon was not cleaned after firing.

After WWII most militaries (including the U.S.) switched to non-corrosive primers (different chemical mix) so that bore corrosion would not be as much of an issue. The downside was the non corrosive primers don't have the same incredibly long lifespan as the corrosive primers.

For example, I've fired ammo from WWII fairly often. If it was stored well, in a stable temperature environment, with low humidity, it works great. However, I've also fired some that was obviously stored poorly because I've had multiple misfires and hangfires with certain batches.

For modern ammo, how long do you need it to be useable for the story? The longer you need, the more the ammo should have been stored in ideal conditions. What you'd want is military ammo, stored in sealed containers, in at least a case lot size. You'd want the ammo to still be in storing/shipping containers of the kind designed for longer term storage, not already broken up into smaller units for distribution, as that means it would have been taken out of the nitrogen sealed containers.

As to duration, anything under about 70 years is definitely possible as I've fired non corrosive ammo made right at the end of WWII.

As to over 100 years, I'd say it's plausible, assumed good storage conditions. Anything further out from that gets iffy. If you want to add some insurance to help "suspension of disbelief" you could have the characters experience some problems with ammo misfiring from time to time.
 

Trebor1415

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As a matter of personal curiosity, would the same apply to shotgun shells?

My Dad's shotgun is loaded with probably 40 year old shells. And there are spares. I've considered taking it to one of the gun shops that have shooting ranges and instructions, to have them unload it for me.

MM

Ammo loaded in a firearm is a completely different thing. It's not protected by the original packaging and may even be corroded inside the gun.

Just FYI, if you take it to a gun range or shop, set it up with them in advance first. Some may tell you they don't want anything to do with it.

Your best bet is a shop with a range because they at least have a range where they can unload it on the range in a safe direction.

I'd drive out there first and talk to the owner. If he agrees, arrange a specific time and return then. Make sure the gun is enclosed in a case. If you need one, buy one. Bring it in in the case, take it the counter and do NOT open the case. Talk to whoever you talked to before to make sure they'll unload it for you. Then give them the closed case and let them take it in the back to open it and unload it.

I wouldn't fire 40 plus year old shotgun ammo stored in cardboard boxes either. Ask the gunshop if they'll dispose of it for you.
 

MaryMumsy

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Thanks, Trebor. That pretty much confirms my suspicions. The shotgun is already in a case.

When we had to evacuate our mountain house is 2011, due to an approaching forest fire, the shotgun was one of the things we took. I asked Dad if it was loaded, and he said: of course.

MM
 

WeaselFire

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As a matter of personal curiosity, would the same apply to shotgun shells?
Plastic hull shotgun shells are fine for many years. Older paper hulls tend to break down sooner.

Unloading the shotgun is quite easy and not dangerous. Shells from the last 40 years don't just go off accidentally, no matter how they were stored.

However, bringing a loaded weapon into a gun shop or range without notifying them first could get you tossed out. If you plan on doing that, leave the gun in the car, walk in and ask first.

FWIW, I shoot military surplus ammo from as early as the 1930's on into the 1990's. I don't have problems with it.

Jeff