How Long Does Ammo Last (Can It Go Bad?)

Contrary to what many people think, ammunition doesn’t have an indefinite shelf life. It also doesn’t take much for it to go bad to the point that it simply becomes unsafe to shoot. I learned this lesson the hard way.

Let me tell you a story…

A Personal Story

The year was 2015, and I had received a new leather holster for my Colt 1911 Series 70 pistol as a birthday gift. This holster was unique in that it was designed with nine cartridge loops sewn into the side to hold spare .45 ACP cartridges. 

Upon receiving the holster, I fit .45 FMJ rounds I had lying around snugly into the cartridge loops. I then wore that holster, with the pistol and spare ammunition in it, on an Idaho elk hunting trip I embarked on that fall. As is the case with many fall hunting trips, there was no shortage of rain outside during the day and condensation dripping in the tent at night. 

I was always careful to take the pistol out of its holster each night of the trip to wipe it down to prevent the possibility of rust and corrosion. The expensive 1911 was too precious to not take special care of like that. However, I left the bullets uninspected in the cartridge loops of the holster, where they remained for a few weeks afterwards.

I went back home (no luck that year) and continued to leave the bullets in the loops. One day a few weeks later, when I dug out the holster back out of the bin where I kept all my holsters, I curiously decided to inspect the bullets I had in the loops. 

To my surprise, and disgust, each one of the nine pieces of brass were completely corroded in an ugly, green-gray coloring that couldn’t just be wiped clean with a little oil as if it were surface level rust. 

I was nineteen years old at the time, and very naive and inexperienced when it came to firearms and ammo storage (and life in general). I was smart enough to ensure I wiped down my pistol from the moisture it was exposed to each night, but I hadn’t given those bullets the same level of thought or attention. 

I realized moisture had seeped into the leather belt and corroded the brass, and it didn’t take very long for it to happen either.

This was my first exposure to the fact that it doesn’t take much to completely ruin ammunition and render it dangerous to shoot. And it was only then that it dawned upon me about how important it is to not be so careless about storing your ammo.

It was only nine rounds that had been damaged, but what if I had stored nine hundred or nine thousand rounds equally as carelessly?

Ammunition isn’t cheap, and as we saw during the pandemic…people will buy it up fast until there’s none of it left on the shelves for months (or years) on end.

Even if you don’t plan on using your ammunition any time soon, it’s still a very valuable investment and would be an equally valuable bartering commodity in the event of an economic collapse or SHTF situation. That’s why it’s so important to extend the shelf life of your ammunition and protect it from going bad as much as possible.

For the remainder of this article, we’ll explore the different factors that can cause ammunition to go bad, and the steps you can take to realistically extend its shelf life for decades. 

Can Ammo Go Bad?

The short answer is yes, ammo can indeed go bad, as my experience I related above shows. 

Just as how your food and water storage can go bad if it’s exposed for long enough to moisture or extreme temperatures, ammunition can go bad if it’s likewise exposed to moisture or extreme temperatures as well. 

Here’s how you can tell if ammunition has gone bad:

• If there are any signs of rust, corrosion, mold, or discoloration of any kind on the lead or shell casing 
• If there is any kind of damage to the lead or shell casing that causes it to look deformed or distorted 
• If the round feels distorted or damaged when you hold it
• If the length of the shell casing has visibly changed since you last saw it or in comparison to other shell casings of the same caliber 
• If the primer of the cartridge appears discolored or deformed in any way 

If you see ammunition with any of the above ‘symptoms,’ don’t shoot it.

What would happen if you did, you might wonder?

What Happens If You Fire Old or Damaged Ammunition?

It’s impossible to know exactly what would happen if you fired old or damaged ammunition without first looking at the ammunition in question.

Any of the following could happen if you attempt to fire old or damaged ammunition:

• The round could misfire, meaning that the powder is not even ignited 
• The bullet may not fully expel from the shell casing or the barrel of the gun, and thus obstruct the barrel (potentially leading to disastrous consequences if the shell casing is ejected and another round is chambered and fired)
• The round could explode to some degree, and damage the internals of the gun or you (this is the worst case scenario)

Here’s a good rule of thumb to follow:

If the cartridges in question have any of the ‘bad signs’ that we outlined above, don’t risk it and don’t experiment.

What Is The Shelf Life of Ammunition?

Most ammunition manufacturers will list an expiration date of around ten years following the date of manufacturing. But truth be told, most ammunition can last for decades beyond that, so long as it’s stored in the right conditions. The ‘expiration date’ that ammunition makers indicate is usually for legal reasons.

A bullet that’s many years or decades old can be just as quality, effective, and safe to shoot as a new bullet. But again, this is only assuming that the ammunition is kept under safe and proper storage practices.

Your ammunition’s shelf life will begin to shorten when it starts to corrode. This is the result of a chemical reaction on the metal when it is exposed for a long enough period to moisture or humidity.

Eventually, the corrosion will get to a certain point that the ammunition becomes unusable, and one of the above listed safety hazards could become a reality if you attempt to fire it.

As a golden rule, DO NOT fire any ammunition that displays visible signs of corrosion of any kind.

Besides moisture, on the opposite end of the spectrum another major enemy of the shelf life of ammunition is extreme heat.

Bullets are constructed out of lead, and when lead is exposed to temperatures of over a thousand degrees Fahrenheit, it will melt.

Rounds that are exposed to a few hundred degrees will cause the primer to pop out rendering the cartridge useless. Granted, you’re probably not going to store your ammunition in those kinds of radical temperatures, but it’s still worth noting. 

So, how can you ensure your ammunition is stored safely and properly so it remains in good condition and safe to shoot for decades?

How To Store Your Ammo Safely (4 Tips)

The good news is that storing your ammunition is a simple process. Here is the process that I use:

1. Store Your Ammunition in Ammo Storage Cans or Containers

Specifically, store your ammunition in storage boxes that are airtight and watertight.

Green metal ammo cans work best for this purpose, not only because they offer excellent protection against the outside elements, but also because you can stack them over one another.

Heavy duty plastic ammo containers are a good alternative option, just make sure the containers you choose are also airtight and O-ring sealed. 

You can either store the ammunition loosely or in the original boxes from the factory; just make sure all the rounds and boxes are fully dry before storing them in the boxes. 

I also recommend that you store one kind of ammunition per storage box for the sake of organization. Label the caliber and the date of storage on the box as well. 

2. Include Desiccants in the Storage Boxes 

Always be sure to include a desiccant in the storage box with the ammo. This will help ensure that the inside of the box remains moisture free.

3. Store Your Ammo In A Dry Location at Normal Room Temperature

Storing your ammunition in metal army cans or ammo containers as described above is important, but where you store those cans and containers is equally so. 

Always store your ammunition indoors in a dry location at normal room temperature. Basements, garages, and storage sheds are often poor areas for storing ammunition just because these are areas that are more prone to accumulating moisture. 

Remember, moisture and humidity is the number one reason that ammunition corrodes and degrades. This is why storing your ammunition away in a cool and dry location is so crucial. Make sure the temperature remains consistent 

4. Limit Exposure To Sunlight 

Always limit the exposure of your ammunition to sunlight, because sunlight can degrade your ammo over time as well. A cool and dry location either in darkness or out of direct sunlight through a window is best. 

Personally, I’ve always stored my ammunition in a closet, because it meets each of the above criteria::

• Room temperature
• Dry
• Out of direct sunlight

Conclusion: How Long Does Ammunition Last?

Ultimately, you need to give the same level of attention to storing your ammunition as you do to storing your food and water.

Food and water are both perishable when exposed in an abnormal or moisture-heavy environment, and ammunition can corrode or decay in the same manner. 

But just like how you can prolong the shelf life of food and water as much as possible with the proper storage methods, you can do the same with ammunition.

Ammunition that is properly stored can last for decades while still maintaining the same performance as when it was originally boxed by the manufacturer.