Subject: Re: Ammo Storage

From: [email-masked] (Gary Coffman)
Date: Wed, 19 Oct 1994 14:55:28 GMT

In article <[email-masked]> [email-masked] () writes:
>I bought a bunch of ammo a year ago, how long is factory ammo good 
>for? How should it be stored to preserve it for the longest time?

I stumbled across several boxes of Great War (WWI) .45ACP ammo at
a country store. It still shoots fine after 76 years. Several boxes
of .30 Luger from 1936 also fired fine. And I haven't ever found any
pre-WWII .30-06 that didn't work. OTOH, I have some 1952 .45ACP non-
corrosive ammo that misfires with great regularity. That was the period 
when non-corrosive ammo was just beginning to be introduced into military 
service. My experience, and that of most experts such as General Hatcher, 
is that corrosive primed ammo has a nearly indefinite shelf life if kept
reasonably cool. My experience with non-corrosive ammo is that it's 
generally good for at least 20 years, but that 40 year old ammo is suspect. 
Whether that's because they hadn't gotten their non-corrosive act together 
back then, or whether it's because non-corrosive priming simply doesn't 
hold up to long storage is still an open question.

The military storage criteria are rather simple, 25 degrees C and
40% relative humidity (non-condensing) is what they recomend for
ammo storage bunkers. Heat is the enemy of ammo. For every 10 degrees
C increase in temperature, the reaction rate doubles. So keeping the
ammo cool slows the chemical reactions that break down powder. The
military suggests ammo be stacked in an open arrangement to promote
good air circulation. Very low humidity is discouraged because of
the danger of static electricity, and because it tends to promote
evaporation of the solvents remaining in the powder and primers.
That can make primers overly sensitive, and cause powder burn rates 
to increase dramatically. 

Double base powders, like Unique and Bullseye, are hydrophobic and
can tolerate long term immersion in water without harm. Single
based collodial stick powders like the Dupont IMR series, can have 
their binders dissolve in hot water. That will alter their burn rate 
dramatically when they dry. Chlorate and lead based priming compounds
are also soluble in hot water, so should not be immersed. 

Basically, if it's comfortable for you, it'll be comfortable for ammo.

Gary
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