Hi all - I have a question regarding ammo storage.  Optimally, I understand that ammo should be stored in a "cool, dry place", but due to space issues, I want to better understand the effects on my LC ammo if I store it in my garage.  I've read the Ammo Oracle FAQ, but it lacks specifics as to what "heat" and "very cold" might be considered to be.

I live in CO where the temps can be extreme.  I do plan to store the ammo in water/air-tight ammo cans, so moisture won't be an issue.  I'm more concerned about the temperature.  Although temps can swing in a day, due to the low moisture content of the air, condensation isn't really an issue here.

Any thoughts?

- Snacko

The problem with temp is that moisture already in the rounds (introduced at the plant, for example) will tend to evaporate and condense inside the round if you heat it way up then bring the temp back down.  Varying temps have this effect on all the components of the round and can break down the chemical structure of the powder.  This is why you should try to avoid temperature fluctuations like the plague if possible.

If it's between 40-70 degrees you SHOULD be fine.  If you get below freezing and back above again all the time, I might wonder if that's a good idea.  Same if you exceed 80 and come down again all the time.

Those are wild guesses, I might try to find some data that quantifies that for the (long overdue) next version of the FAQ.

Thanks Tat for your input.  With the tempretures you provided, I don't think my garage would qualify as a good storage location.  Though the amtomsphere is dry here and I won't have to worry about water leakage, the tempretures will dip below freezing in the fall and winter and surely go above 80 degrees in the summer.  I guess I'll have to search for an alternate local.

Thanks again,

- Snacko

I personally don't think storing it in your garage should be a problem, and low temps shouldn't be problem. I think it is high heat that you should be concerned about. A pamphlet from my Aliant/Hercules reloading manual says "that if the powder has a sweet smell that the powder has deterioated and shouldn't be used." I don't know eexactly what temps are considered, but I had a thermometer in my car, and in sunny So. Calif day, it hit something like 160 degress F. So I don't recommend storing your ammo for extented periods of time inside your car with the windows up during the summer.

Tat is right (as usual) - the fluctuations do the most harm.  Earth covered magazines (also called "igloos") provide the best storage because they maintain a steady temperature.  

Not many of us store personal ammo in igloos (though I suspect a few readers have large quantities...), but IMO a garage in CO is not the best place for long-term storage.  

I could not find a precise reference, but from USAF TO 11A13-10-7, Specialized Storage and Maintenance Procedures, Small Arms Ammunition, Work Package 40, para 11, Special Storage Instructions:  

  Extreme heat may cause dangerous pressure
  to develop and a high combination of high
  temperature and humidity will cause
  propellant to deteriorate rapidly. Tracer
  ammunition is subject to rapid deterioration
  when damp.  

And from TM 9-1300-214, Military Explosives, para 14-4c(1), Storage of Explosives and Ammunition:

  Sudden changes in temperature may damage
  airtight containers or may result in
  excessive condensation of moisture.

Yes, military ammo is shipped/stored in CONEX containers and MILVANs all the time, and it's possible MilSpec IMR powder is designed to withstand temperature extremes.  Still, I do not recommend a garage for long-term storage.      

Thanks SIGman for your add'l info.  I guess I'll have to find an alternative depot for my ammo.

- Snacko