Long Term Ammunition Storage

Published by the LearnAboutGuns.com Author on August 26, 2009 at 12:01 am
LearnAboutGuns.com > How-To Guides and Other Info > Long Term Ammunition Storage

Prior to the current ammunition shortage,  I generally kept only a small amount of ammo at home.  I never really bothered to stock up, since I could always buy plenty of ammo at a reasonable price from my local gun stores.  But nowadays, ammunition is in short supply, and sometimes can’t be had at any price.  For example, I’ve wanted to go shoot my Springfield XD40 a few times this summer, but didn’t have any ammo (other than a limited amount of self defense ammo) on hand, and all of my local gun stores were completely out of .40 S&W.  Not wanting to repeat this experience, I’ve decided to stock up on ammunition.  Below are my suggestions for the long term storage of ammo:

Reasons to stock up on ammo

There are multiple reasons why stocking up on ammo is a good idea.  Firstly, in the event of a future shortage, having ammo on hand can make life easier.  Instead of going from store to store to find ammo, one can spend that time firing their existing ammo, and restock when the shortage ends.  This would also likely save money, since ammo prices go up during a shortage.  Secondly, it is often possible to save money buy purchasing ammo in bulk.  Thirdly, in the event of civil unrest, terrorist attack, or natural disasters, having a large enough supply of ammo on hand may be the difference between life and death.  While I certainly hope that my life continues to be free from such unpleasant events, having some extra ammo on hand is a good insurance policy.

Long term ammo storage considerations

Small arms ammunition can be rendered ineffective by moisture, oxygen, and temperature extremes over time.  These factors can render the gunpowder and primer ineffective, damage the casings, and damage the bullets.  The goal when storing ammo is to mitigate these factors, but to do so in a cost effective manner.  In other words, a balance should be struck between the amount of money and effort spent to protect the ammo, and the return on that investment.  For example, one could spend thousands of dollars to perfectly store and preserve a few hundred dollars of ammo, but that would be rather wasteful.  (Some sort of triple sealed storage system, where the ammo is in an argon filled container and kept at the perfect temperature and pressure by a computerized monitoring system comes to mind…)   On the other hand, throwing valuable ammo into a corner of one’s flood-prone basement isn’t a wise choice either.  Below is the approach that I’ve found to be most practical.

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My long term ammo storage method

I purchased the following items: military ammo cans (with rubber seals), desiccant packs, oxygen absorbers, and the ammunition itself.  Everything but the ammo can be purchased from Amazon.com.  For those looking for ammo online, I like ImpactGuns.com.

After I got the ammo home, I placed it in my gun safe for a few days to reduce its humidity, since my gun safe almost certainly has a lower humidity level than the store’s shelf or warehouse. This will help ensure that the desiccants are as effective as possible at keeping moisture levels down once the ammo is in the ammo cans.  I also take this time to inspect the ammo for any visible defects, since I would hate to waste the space storing damaged ammo.

Next, I load the ammo into the ammo cans.  I generally keep the ammo in its boxes, since they provide some padding and make it easy to neatly stack.  I do try to use up as much space in the ammo cans as possible, so that the oxygen absorbers and desiccant packs can do their jobs more efficiently.

Working quickly on this next step, I put the desiccant packs and oxygen absorbers into the ammo cans, and seal the ammo cans.  Time is of the essence here since both the desiccants and oxygen absorbers will begin to work as soon as they are taken out of their airtight packages.  The desiccant packs absorb moisture from the air in the ammo can, protecting the ammo from excessive humidity.  The oxygen absorbers absorb the oxygen from the air in the ammo can, similarly protecting the ammo from oxidation. The combination of low humidity and low oxygen levels should virtually eliminate the chemical changes that normally degrade ammo.

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Finally, I label the ammo can with its contents and the date, before storing it on the floor of my gun safe.  I keep it in the gun safe so that it is safe from burglars, protected from temperature changes, and because the extra weight in the safe will make it slightly harder for a thief to steal the whole safe.

Closing remarks on my long term ammo storage method

First, I want to acknowledge that my method is probably more preparation than is really need.  The military stores ammo in these same ammo cans, but without desiccants or oxygen absorbers, and their ammo is fine for decades.  But, as I mentioned above, my goal was to store my ammo in the most effective manner possible without really wasting time/effort.  Since enough oxygen absorber packets/desiccant packets for 4 ammo cans costs only $20 and they are easy to use, while the ammo to fill those cans could easily cost over $1,000, I find this to be a reasonable expenditure.

As far as the merits of my storage method, the use of US government ammo cans is about as standard and time-tested a method as possible.  The use of desiccants is also a traditional method of protecting ammo from moisture.  The only thing that is not as standard is the use of oxygen absorbers.  Oxygen absorbers have been around for a while, and are common in beef jerky packages.  They help keep food fresh and vitamins intact by removing the oxygen from the package.  Use of oxygen absorbers in conjunction with ammo storage is somewhat newer  -but that is not to say that their effects are unknown.  The chemistry underlying the effects of oxygen absorbers are well understood, as is the chemistry of small arms ammo.  The simple chemical reaction that powers the oxygen absorbers (the oxidation of Iron II) does not pose a threat to ammo.  Since oxygen absorbers remove virtually all the oxygen from the ammo cans, the pressure in the ammo cans will drop by about 21% (since air is about 21% oxygen, 78% nitrogen, and 1% various other trace gases).  This pressure drop is quite gradual, and does not pose a threat to the ammo (or the ammo can).  Ammunition carried aboard in the cabin of a commercial airliner undergoes a greater and more rapid pressure change, and is not harmed.  Ammo flown in the unpressurized cargo hold of transport aircraft undergoes an even more rapid and drastic pressure change, also with no ill effects.  But just to be sure, I checked on some of my stored ammo after about a week, and found that it was undamaged by the pressure change.  Accounts from others who have used oxygen absorbers (or even vacuum sealed their ammo) confirm that oxygen absorbers are safe for ammo.

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A note on ammo cans

I prefer to buy new ones, instead of used military surplus ammo cans.  That is because I have greater confidence in the new ammo cans’ integrity – especially the rubber seal near the lid.  Since the price difference between a new and used ammo can is only about $10, I’m willing to spend that extra money to better protect the hundreds of dollars of ammo that may go in that can.

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  • Anders

    New US Army ammo cans? Link please.

    I didn't know they sold new ones. Nor can I find them.

  • https://www.learnaboutguns.com LearnAboutGuns.com

    I've seen new ammo cans on Amazon before, but can't seem to find any right now. The ones I used actually came from Gander Mountain, since it was cheaper to buy them locally and pay tax than to buy them online and pay for shipping…

  • BasinBictory

    Maybe I don't have ammo storage problems in mild-weather California, but I first got my start in firearms with surplus military rifles, and much of the surplus ammo I bought for them was Eastern-Bloc stuff that had likely been stored in warehouses without the benefit of air conditioning or dessicants, and almost all of it was fine. Obviously you don't want to store your ammo anyplace likely to get wet, but other than that, I think ammo is pretty durable and storage shouldn't be that big a deal.

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    I've heard similar things from ex-military people at work, and I believe that both you and they are very correct – ammo is durable and lasts for decades even in less than perfect conditions. I'm sure that the ammo would last for decades just sitting on the floor of my gunsafe.

    But, as I mentioned in the article, I'm happy to spend a few more dollars to better store the ammo. This is especially true of the self defense ammo, since if I ever have to use it, I wish to be supremely confident of its reliability. The total cost of the desiccants and oxygen absorbers was about $20, which is a good investment IMO.

  • BasinBictory

    In the case of self-defense ammo, I think it should be used up and rebought (fresh) fairly often. When you need your ammo to work, absolutely every single time – then I would definitely insist on new, factory-loaded rounds no more than say – a year old.

    Also – another good dessicant material which is commonplace, cheap, and available at any Wal-mart or grocery store, is kitty litter. Put some in a small plastic container (like a small Tupperware), and stick it in your gunsafe. I personally like it because it is more available, and buying it doesn't raise eyebrows at the checkout counter the way buying most other gun paraphernalia does.

  • https://www.learnaboutguns.com LearnAboutGuns.com


    For the self defense ammo in my guns on a regular basis, I do keep the ammo as fresh as possible. But my goal here is long term storage or a sizable quantity of ammo. Firing off the ammo every year would run contrary to the purpose here, since I wish to have lots on hand. Given the virtually oxygen free and very low moisture environment, I doubt that this ammo will be any less reliable next year than ammo that is brand new.

    The use of kitty litter as a desiccant concerns me. Desiccants are made only of specific chemicals which we know won't harm ammo. Kitty litter may have various other compounds in it that could harm guns or ammo over time. I'm not saying that I *know* it can cause harm, but rather that I don't know the formula used by each manufacture or that they will stick with their formula over time. Given the low cost of normal desiccants and the ease with which they can be purchased in person or online, I can't see a good reason to use anything else for moisture control.

  • BasinBictory

    What I meant by "recycling" your defensive ammo was simply that practicing often with your carry loads is a good idea, and once you've popped off a hundred rounds or so of it, to buy some more – keeping your overall stock of defensive carry ammo fresh. If you're planning on storing thousands of rounds, then yeah, obviously you're not going to shoot off that many at a time (unless you're really, really lucky!)

    As far as kitty litter as dessicant – IIRC, the appropriate type to use is the 100% silica kitty litter, but you're right in that dessicant is inexpensive, so substitutes are probably not necessary.