View Full Version : Ammo and freezing temps?
November 20, 2000, 15:38
I am wondering what the effects of below zero temps on ammo are. The reason I ask is because If I order some surplus this time of year it will probably sit outside for a few hours until I get home. So will this prolonged exposure to 20 degree temps hurt the ammo?
November 20, 2000, 16:00
My understanding of most surplus ammo is that it is packaged for long term storage. These things sit for several DECADES, without attention and are expected to function that way. The only possible problem involves ammunition which isn't sealed tightly (that is, bullet to brass seal), and over time, could absorb moisture into the powder. The other seal is the primer to case seal, which could yield similar results if moisture gets in there.
I once reloaded some shotgun shells which I had tried to clean up with soap and water. I thought they had dried out thoroughly, but was obviously mistaken when on the trap line during league shooting, there was the sinking sound of "PULL!....pfft...pop", and a dull orange fireball emerging from the barrel. This was followed by a shower of lead shot falling on the trap house 16 yards away.
A day in the cold weather for military surplus ammunition should be nothing to worry about.
[This message has been edited by vfrdirk (edited November 20, 2000).]
November 20, 2000, 22:54
From my expeierence I have found that cold weather does not impair ammunition. But you have to be careful when shootong at cold temeratures. By cold I mean anythng below -20F. I have found that if you are not careful the condinsation that forms in the reciver will condense and freeze causing an assortment of problems with the rifle or hadgun.
Where are you at? I am up in Fairbanks, AK and it gets mighty cold out during the winter months, -40 to -50 is not uncommon, and as you know when you have to shoot you have to shoot. http://www.fnfal.com/forums/biggrin.gif
FEAR THE GOVERNMENT WHO FEARS YOUR GUNS
A Philosophical Mind
November 21, 2000, 09:16
From what I've heard, it's repeated sudden temperature swings that can degrade the powder in ammo.
November 21, 2000, 10:36
Temperature does affect ammunition performance. But it isn't supposed to be permanent unless the integrity of the cartridge is compromised.
Guns & Ammo had an article a few years ago about the effects of ammo loaded to the limit. It discussed what would happen if the ammo was then placed in the trunk of your car on a very hot day. You could gain as much as an extra 10,000 psi boost in chamber pressures. That boost could push what was a hot but safe load way over the limit.
It stands to reason that cold temps would have a similar inverse effect. To verify how much, you'd have to get out and chronograph during freezing temps and then calculate your bullet drop accordingly. Also, as air thickens during freezing temperatures, your ammunition's ballistics may also be affected.
November 22, 2000, 20:40
Heat is the biggest threat to long shelf-life. If ammo is left in a hot environment, I believe 90 F or higher, for long periods of time, the powder with begin to deteriorate. While I am not sure exactly why this happens, it is probably due to the components in the powder itself, seperating out. There has been stories of some surplus ammo from the gulf war that was being sold. It had been sitting in a Saudi warehouse for a few years with out any air conditioning. People who bought some of this stuff were having problems with rounds being too hot or being duds.
Ammo exposed to repeated large fluctuations in temp can have its powder degrade too. Since powder is like any other material, it will expand and contract with temp change. If this happens repeatedly it could cause the powder to start breaking apart.
Having the ammo exposed to the cold is not a big deal. However, if the ammo is not in sealed packages, when you bring it in, moisture could condense on the brass. Just let the ammo sit out for a few days at room temp, before storing in any air tight containers.
Moisture is not that big of a deal if you are dealing with milspec ammo. Since the primer and bullet are sealed, there is little chance moisture will reach the powder. However, the brass could start to corrode if exposed to high humidity or water for extended periods of time.
Ammo is not really that fragile though, to the elements. The above concerns are only issues if the ammo has been exposed to these conditions for a number of years. The best way to store ammo, is in the 50 to 80 F range, in air tight containers with desicant just to be safe. In these conditions, ammo should last longer than you.
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