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cosine
09-11-2013, 11:43 AM
The general advice I've always read for long-term ammo storage (greater than 1 year) is to keep it "cool and dry." What's considered "cool and dry"? Does it mean to maintain the ammo temperature to less than 90 deg F? 100 deg F? Or not permit the temperature swings in storage to exceed (for example) 60 deg F to 90 deg F?

And regarding dry... does that mean store the ammo where the relative humidity is less than 90%? 80%?

I have (for my means) a not-insignificant quantity of .22LR, 9mm, and 5.56 which I would like to ensure is stored properly to protect my monetary investment. I can control the ambient temperature in my residence to between 60 deg F (winter low) and 90 deg F (summer high) fairly easily, but there have been days this past summer where the relative humidity has been around 85%-90%. All of my ammo is currently stored in the cardboard cases in which it came. Do I need to be concerned about the temperature range swings in my residence between summer and winter? If the relative humidity has been at times 80%-90% should I be storing the ammo in waterproof ammo cans with desiccant?

Thanks for your help!

SecondsCount
09-11-2013, 07:22 PM
I would be more concerned with the dry part than the cool part.

Keeping the humidity below 60% and the temperature cool (below 80F) would be a good start.

JodyH
09-11-2013, 08:49 PM
I shot some .30-06 that was stored in my Grandparents unheated, uninsulated garage since at least the '50's, worked perfect.

JAD
09-12-2013, 07:57 PM
Friend of mine who shoots a little and owns a bit of land once stored a winter's .45 reloads in a trash can (yes, mostly full). Then put it in one of his too many sheds. Then loaded some more and forgot about it. Ten years later he's cleaning out the shed and the (open) trash can turns out to have been under a leak. Trash can is full of water and probably was during the entire Clinton administration.

He shot it all in a summer. There were two failures to fire.

SecondsCount
09-12-2013, 08:47 PM
Friend of mine who shoots a little and owns a bit of land once stored a winter's .45 reloads in a trash can (yes, mostly full). Then put it in one of his too many sheds. Then loaded some more and forgot about it. Ten years later he's cleaning out the shed and the (open) trash can turns out to have been under a leak. Trash can is full of water and probably was during the entire Clinton administration.

He shot it all in a summer. There were two failures to fire.

That had to be some of the nastiest looking ammo...

-06
09-13-2013, 01:25 AM
Bet that was awful looking brass/boolits. Cleaned up some nasty stuff also that fired well. Have a soft brass wheel on a small bench grinder and a jewelers wheel on the other end. Does marvelous job of cleaning polishing things. Have fired some cloth belted '06 that had to be 50 yrs old--they all went bang. I keep ammo in ammo cans with a desiccant pack tossed in(on top of a piece of cardboard).

BLR
09-13-2013, 06:35 AM
humidity won't hurt long term storage of ammunition or components, unless a dry out period is not possible. Most powders are stored underwater, as a matter of fact. I've seen the original lot of Bullseye, which every so often is pulled out from wet storage, dried, and used to compare with current lots.

Ideally, storage would be around 60F and 0% humidity to keep corrosion as minimal as possible. Also, lower temperatures keep free ammonia from escaping the powder and embrittling the brass.

JAD
09-13-2013, 10:26 PM
That had to be some of the nastiest looking ammo...

He shot it as was, and it fed in his stock colt.


Jon
KC

uechibear
09-17-2013, 10:12 AM
I was wondering the same thing recently. I looked around and found a post that seemed good enough that I saved the information. A guy had 100K rounds stored in a garage in Texas, and his question was answered by someone who was stationed nearby in the military. He said they store their ammo in structures like these: Explosive Storage Magazines (http://www.armagcorp.com/explosives-magazines)

Here is what he wrote:


We check magazine temps every day.

If the internal magazine temp is at 100 to 110*F, we are supposed to artificially cool the mag (could be as simple as putting up a sun shade, or as much as keeping a hose running on it.)

When it hits 110-120*F, it's supposed to be cooled as well, and when the cumulative time exposed to these temps reaches 500 hours, the ammo in that mag is supposed to be expended on a priority basis.

When the mag temp goes to 120-130*F, and the number of hours spent there is recorded, same as above. When you hit 100 hours of temps over 120 before you get 500 hours of 110-120*, use it on a priority basis.

When it gets above 130*, the ammo should be turned in and not used.


I'd wager the inside of your garage doesn't get much higher than 100. I'd say don't worry about it. The highest mag temp I've seen is 109.

Also, it should be noted that just because ammo goes BANG, that does not mean it hasn't been altered by storage conditions. Another poster in the same thread provided chrono data on ammo that had been kept in his car trunk in the Arizona heat for a year, and it showed a large increase in Standard Deviation and Extreme Spread. I'm no expert, but it sounds like that ammo could be less accurate than when it was new.

I'd be interested in comments about any of this from knowledgeable people here.

David Armstrong
09-17-2013, 11:12 AM
Back before I knew any better I shot up a lot of .45 ACP ammo that was in sealed military containers from WWI (yes, one) that had been stored in a variety of houses over the decades without any unusual protection. IIRC it all worked fine. I've never done anything extra with mine, it is all stored in a closet inside government ammo cans and I haven't had any problems over the last 40 years or so.

Rich
09-22-2013, 08:30 PM
I keep my SD loads inside the house. Range ammo I seal in GI cans and store them in garage off floor.

I shot a box of PAPER 12GA that my grandfather had back in the early 90`s
As far as I know it was stored in a sock drawer.