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Does Ammunition Have a Shelf Life?

Does Ammunition Have a Shelf Life?

I am a new gun owner, so I am behind the power curve in equipping myself with guns, ammunition and the support material necessary to stay in the personal-protection arena for the foreseeable future. After seeing the collections of equipment some of my friends (who have been into guns and hunting longer than me) have amassed, I realized that bulk purchases of ammunition where it could be found would be a smart move. That is until my wife, who is a very smart shopper, asked me what the expiration date on the ammunition that I was purchasing was.

She was inferring that, like food and other expendable commodities purchased in today’s society, the ammunition’s useful life was finite and would have to be replaced if not shot by its expiration date. This led to a conversation about how much did I really need, as opposed to how much I would like to have, as ammunition is hard to find—especially in popular defensive calibers. I would like to buy as much as I can afford, but not if it will go bad before I can shoot it.

Does ammunition have shelf life? Is there an expiration date printed in an obscure location on the box it comes in? If so, where do I find it? How do I know how long the ammunition I purchase is good for before I have to replace it?

Like I said, I’m new at this so your help would be greatly appreciated.

Paul Smythe
Brunswick, ME

If it makes you feel any better, you have a lot of company with the same questions. With gun, ammunition and accessory sales at unprecedented levels, shortages stimulate panic buying just to have something, without fully understanding the scope of what is being bought.

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. 

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