Ammunition Shelf Life
BY Herschel Smith
3 years, 10 months ago
Once the ammunition is purchased, where and how it is stored will determine how long it will be viable for its intended use.
Heat and moisture are the two most prevalent enemies of ammunition, followed by chemical contamination.
Temperatures consistently in excess of 150 to 170 degrees Fahrenheit tend to affect the propellant in a negative manner. These temperatures can be reached in car trunks, metal buildings or other uninsulated enclosures subjected to direct sunlight—especially in the southern tiers of the United States.
Anytime ammunition is subjected to continuous exposure to moisture, corrosion is likely to occur, which degrades the performance or disables the usability of the cartridges all together.
Chemical contamination is sometimes the silent killer of ammunition. Although much of today’s quality ammunition is protected by sealant-treated primers and bullets during manufacture, exposure to penetrating oils or cleaning solvents will degrade the sealants over time, thereby neutralizing the priming compound, the propellant or both, rendering the cartridge useless.
Ammoniated solvents used for removing copper from a bore are detrimental to brass cartridge cases, even with minimal exposure. Since brass is 70 percent copper (with the remaining 30 percent being zinc), ammoniated solvents can create a dangerous condition causing the brass to crack without having been fired. This could cause a hazardous pressure release during firing due to the weakened condition of the brass case.
Ammunition storage can be as simple as storing it in a safe area similar in environment to the office within which you work or the home in which you live. Keeping the temperature and humidity levels similar to what is comfortable for you and the family is an easy way to stay well within the range suitable for ammunition storage.
Many individuals who purchase and store quantities of ammunition are served well by storing it in sealed, military-surplus ammunition containers. Kept in a climate controlled, secure location, away from unauthorized personnel, these containers will preserve the ammunition indefinitely.
The reason there is no expiration date on a box of currently manufactured ammunition is because, when stored properly, it is projected to have an unlimited life span.
As an aside, I personally have fired ammunition loaded more than 100 years ago with excellent results. Advancements in primers, powder, cases, projectiles as well as in storage containers and accessories have improved the reliability of ammunition to a point that, properly treated, there is no reason for concern for your ammunition’s longevity.
Use of a sealed container (like a safe) along with desiccant would also help.
On February 1, 2021 at 12:07 pm, Sanders said:
Oldest ammo I’ve shot was 1929 stamped steel cased Czech 8mm Mauser.
It was an experiment to see if it would shoot. I had two boxes of 15 and out of the 30 rounds, I had 10 that would not go off. Several needed more than one strike on the primer. It was a good practice to see if I was flinching. Corrosive as all get out, as you would expect. Cleaned the rifle over 3 days to make sure I got all the salts out, though.
On February 2, 2021 at 2:01 pm, Silence DoGood said:
It all comes down to how it’s stored.
When Laflin & Rand created Bullseye powder in 1899, they stored a sample from the first production batch in a large glass jar (more like a small vat) filled with distilled water. And that same vat is still being maintained. Laflin and Rand became Hercules and then Hercules became Alliant but they still take a small sample of the the 1899 Bullseye powder out now and again, dry it out and shoot it in a 12-gauge test load. Almost 125 years on, it still shows minimal signs of deterioration.
Which is especially remarkable when you consider that the coatings created to stabilize the individual granules against age deterioration weren’t invented until 1910! The obvious implication being that any powder made from 1910 onward should be even more stable over time.
The thing about explosives is that they’re made to be ‘reactive’ for a reason. Substances that aren’t reactive DON’T EXPLODE. Or conflagrate. And if it isn’t reactive enough to support conflagration, it isn’t much use as a firearm propellant. It’s in the nature of the beast.
And on the whole, explosives are pretty much polyamorous. They’ll react with most anything available. Like air. But like most chemical reactions, the rate of reaction varies directly with the heat available. Less heat equals a slower reaction equals longer lifespan.
So keep your ammo someplace cool and dry and stop fretting over it.