Best Conditions for Storing Ammo?

[Justin]

I've always heard that you should store ammo somewhere cool and dry where the temperature is fairly stable.
Lately I've been giving some thought to where I store my ammo, and it seems like the temperature has a tendency to fluctuate. For grins, we'll say that the temperature in the room can fluctuate 20* in a day, from 60* to 80* or so.
Am I running the risk of causing damage to ammo stored in this room?

 

[Art Eatman]

That's a trivial fluctuation, as far as ammo is concerned. No danger.

Long-term storage in temperatures seriously higher than 85 to 90 degrees will reduce the performance insofar as muzzle velocity. It won't be necessarily large, however. I have some .243 ammo I loaded in 1968 which has occasionally been in 100-degree temperatures in a mobile home. Groups fine, but prints a couple of inches lower than newer stuff.

Humidity can be a problem for ammo in the original paper boxes, with a grunge buildup on the outside of the brass. This can usually be cleaned off with steel wool. In plastic boxes, no problem.

Age doesn't make a lot of difference. I have some GI .45ACP hardball marked "EC 43" which still goes bang.

Art

 

[0007]

Stick it in GI can and keep enough space between the cans for air circuilation. ( I use 1 X 2's between stacks). As long as the cans are closed, the ammo may or may not out-gas enough to displace the air internal in the can and self pressurize the can.