How To Tell If Ammo Is Bad

How To Tell If Ammo Is Bad (3 Signs)

There’s an old saying that nothing lasts forever, and that’s true with ammo. Even though ammunition can last for years or even decades when properly stored, once it’s gone bad, it’s irreversible.

Here are 3 ways for how to tell if ammo is bad:

  1. Changes or irregularities in shell casing length
  2. Corrosion, discoloration, mold, or rust
  3. Deformities or distortions

If you’re a gun owner, you know that bad ammo can cause serious problems, from misfires to gun malfunctions.

So how can you tell if your ammo is still functional?

Check out these 3 telltale signs, and learn how to spot changes, corrosion, deformities, and more – before it’s too late…

People have also been storing more ammunition than normal lately due to the recent ammo shortages and major societal and economic uncertainties that we have all witnessed over the last few years.

But as you’re likely already aware, ammunition is not cheap, and buying large amounts of it is a significant financial investment. As with any investment, you want to make sure your ammo investment is protected.

But if you do shoot ammunition that has gone bad, the consequences can be catastrophic if not outright fatal. This is why it’s not only important to know how to store ammunition properly, but also to properly diagnose ammunition so you know if it’s gone bad or not. 

After all, you wouldn’t want to eat a juicy ribeye that’s become discolored or drink milk that’s gone rotten. All the same, you don’t want to shoot ammo that’s become rotten either. 

But how can you tell if ammo has gone bad? That’s one of the primary questions we’ll answer in this article.

How Long Does It Take For Ammo To Go Bad?

How Long Does It Take For Ammo To Go Bad

There is no definitive answer to this question because there are many factors that can cause ammunition to go bad, including humidity, moisture, unusually cold or hot temperatures, or exposing your ammunition to the elements. 

Each of those factors can take a different length of time to cause ammo to go bad to the point of it becoming unshootable. For example, exposing your ammunition directly to water can cause it to discolor and corrode very quickly. 

Most ammunition manufacturers will list an expiration date on their ammo boxes of ten years following the manufacturing date under proper storage conditions (by proper storage conditions, we mean storing ammunition in ammo storage cans and in a dry location at normal room temperature – more on this later).

The shelf life of ammunition begins to shorten once the round starts to corrode. Corrosion occurs from a chemical reaction on the metal when it has been exposed for a long enough period of time to humidity or moisture. Eventually, the round will corrode to a point that it’s no longer usable. 

And as a golden rule, you NEVER want to fire ammunition that has shown any signs of corrosion at all.

So how can you definitively tell that ammo has gone bad? We’ll talk about this next.

How Can You Tell When Ammo Has Gone Bad?

How Can You Tell When Ammo Has Gone Bad

You can tell if ammo has gone bad if any of the following ‘symptoms’ appear:

1. Change in the Shell Casing Length 

If the length of the shell casing is longer or shorter than you noticed before, or if it’s longer or shorter than the other shell casings of the same caliber, it’s a good sign that something is wrong.

2. Corrosion, Discoloration, Mold, or Rust

Any kind of corrosion or discoloration on either the shelf casing or on the lead bullet is a crystal clear sign that the ammunition has gone bad. 

3. Deformities or Distortions

Has the shell casing or lead become visibly deformed or misshapen in any way? This is another clear sign that it’s gone bad. 

Keep in mind that some deformities and distortions in ammunition cannot be initially seen but can be felt. If you pick up a round and it feels ‘off’ inspect it closely. There might be something off upon closer inspection. 

You never want to risk shooting ammunition that displays any of the above kinds of symptoms, because…

What Happens If You Shoot Bad Ammo?

What Happens If You Shoot Bad Ammo

So what happens if you fire a round that displays any of the above symptoms?

Just like how there is no definitive answer to the question of ‘how long does it take for ammo to go bad?” due to the number of factors that can cause it to go bad, there is also no definitive answer to the question “what happens if you shoot bad ammo?”

But let’s put it this way: if you shoot bad ammo through a firearm, the consequences can range from a simple misfire to a catastrophic accident that causes the gun to explode in your hands (which can result in severe injuries or even death).

This is why you NEVER want to take the risk of shooting bad ammo that displays any of the above symptoms that we’ve discussed. It’s simply not worth risking your vision, your fingers, or your life to attempt to shoot a round that looks bad. 

If any ammunition you have in your possession displays the symptoms we’ve outlined above – SAFELY DISPOSE OF IT. 

Ammunition that has become corroded or rusted will inflict more friction on the internal surfaces of the gun. You’ll likely notice greater resistance with feeding the round into the magazine or racking the slide to chamber it (and if you do feel greater resistance performing these actions, STOP what you’re doing and inspect the ammunition immediately). Again, it’s never worth attempting to shoot bad ammunition under any circumstances. 

What Can Cause Ammo To Go Bad? (5 Culprits)

What Can Cause Ammo To Go Bad

The following are the most common ‘culprits’ for why ammunition can go bad:

1. Product Defects 

Product defects can happen with ammunition as well. As a general rule, defections are more commonplace with rimfire ammunition than centerfire ammunition. This is because the primers with rimfire ammunition are usually more susceptible to having issues due to the inherent nature of rimfire ammunition design. 

Complicating matters is that defective ammo usually doesn’t exhibit the above symptoms that we’ve covered. In the event that you fire any ammunition that exhibits issue while firing, always point the firearm in a safe direction and attempt to safely remove the round from the chamber. 

2. Old Age

As mentioned above, most ammo manufacturers indicate a shelf life of ten years for ammunition, but some ammo can last for years longer than this when stored in optimum conditions.

There is some ammunition, for instance, that has been stored since the beginning of the 20th Century and could be safely fired today if it was stored properly all that time.

But ammunition that’s older will have had more time to degrade, meaning that it’s always riskier shooting older ammo than newer ammo.

For this reason, if you shoot ammo that you know is old, always carefully inspect the ammo before attempting to load it into your gun or magazine.

3. Physical Damage

Is your firearm experiencing a stovepipe or a double feed? Take a look at the shell casing. If there are any scratches, burrs, bulges, or deformities in the casing you have your culprit. 

4. Reloading

Reloaded ammunition is usually more ‘suspect’ than ammo that was originally loaded in a factory. This is especially true if you don’t know the origin of the reloaded ammo and who reloaded it.

Only shoot reloaded ammo from a professional who you trust.

5. Water Damage

Ammunition that hasn’t been stored properly is always at greater risk of going bad and being unsafe to shoot.

The biggest enemy of ammo is moisture, and if moisture gets into the shell casing and damages the powder it can completely ruin the round.

But even if moisture doesn’t affect the powder, if it stays in contact with the shell casing long enough it can cause the aforementioned chemical reaction that will cause it to discolor and corrode.

3 Storage Tips For Ammo

Storage Tips For Ammo

You can follow these three critical storage practices to prevent your ammunition from going bad:

Use Ammo Storage Cans

Always use storage cans or containers that are made specifically for the purpose of storing ammo.

Metal ammo cans or heavy duty plastic ammo containers are the best choices. Not only do these kinds of cans and containers protect your ammo against moisture and other outside elements, they are useful for organization as well.

Store The Ammo At Normal Room Temperature

Storing your ammunition at normal room temperature will ensure it isn’t exposed to major fluctuations in temperatures that can cause it to go bad.

Make Sure The Ammo Stays Dry

Remember, moisture is the number one enemy of ammunition that will cause it to go bad.

Always store your ammunition indoors and include desiccant packs in the storage cans, and open the cans at regular intervals (such as every few months) to make sure that no moisture has accumulated inside. 

Recap: How to Tell if Ammo is Bad (0r Still Functional)


In short, it’s generally easy to tell if ammunition has gone bad:

Corrosion, discolorations, deformities, and any changes in the length of the shell casing are the most obvious signs that your ammunition is no longer safe to shoot.

Remember, never risk shooting ammo that shows any of the above signs of corrosion or deformities.

Instead, safely discard the ammo that displays the symptoms we’ve covered and move onto another ammunition that doesn’t show any of those signs.

Knowing how to detect ammo that’s gone bad can literally make the difference between whether or not you experience a major catastrophe the next time you hit the range. 


How Do You Know When Bullets are Bad?

Indicators of bad bullets can include visible corrosion, damage, or deformities, as well as abnormal discharge sounds or misfires when shooting. Inspecting ammunition for these signs can help in identifying and avoiding the use of compromised rounds.

What Makes Ammo Bad?

Ammunition can become bad due to factors like improper storage, exposure to moisture, extreme temperatures, or age. These conditions can lead to corrosion, powder degradation, or primer failure, affecting the ammunition’s performance and safety.

What Happens if You Use Bad Ammo?

Using bad ammo can result in misfires, duds, hangfires, or even catastrophic firearm failures. It compromises shooting accuracy, safety, and the integrity of the firearm, posing risks to the shooter and bystanders.

What are the Best Ways to Identify Ammunition?

Identifying ammunition involves checking the headstamp for caliber and manufacturer, examining the overall condition for any signs of corrosion or damage, and ensuring it matches the firearm’s specifications. Proper knowledge and regular inspection practices ensure safe and effective ammo usage.

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