Does Ammo Go Bad? [Storage Tips & Average Shelf Life]

When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Perhaps you’ve just inherited an old firearm from your Great Grandad along with boxes of old ammunition.  You’re eager to take it to the range, but you’re not quite sure whether it’s a good idea to fire that old ammo.  Maybe they’re safe.  Perhaps they’ll explode in your hands.  Is there a way to tell and how old is too old?

While some manufacturers may specify a shelf life on their ammunition, properly stored ammunition can last indefinitely.  Conversely, improperly stored ammunition could be subjected to rapid changes in temperature and moisture, which will degrade the integrity of the ammunition over many years.

Maybe you have just inherited, found a bargain on old ammo, or are planning to buy bulk ammo to store for a rainy doomsday. 

Either way, you need to understand how storage affects ammo’s shelf life and what warning signs to look for in old ammo.

Does Ammo Go Bad

Ammo And The Elements Don’t Mix

The biggest natural enemy of ammunition is moisture.  Where there is moisture, there is oxidation and rust.  In the context of ammunition storage and shelf life, moisture is caused by an effect known as “thermal shock.”

Thermal shock occurs during rapid or drastic changes in ambient temperature, leading to condensation forming outside or inside the brass case. 

Warning Signs Of Potentially Bad Ammo

When ammunition has been exposed to condensation and other elements for a long time, there are usually pretty obvious tell-tale signs. 

Lighter forms of exposure will usually present in the case turning from that beautifully-shiny brass to a dull or even slightly matt-greyed appearance.  This is caused by early oxidation setting in.  In more advanced stages, you will likely see green patches forming outside the case.

An even more severe sign to look for is when oxidation has become corrosion, which will appear in a chalky-white layer.  Corrosion results from the formation of brass salts and will almost certainly degrade the quality and integrity of the casing. 

The Dangers Of Bad Ammunition

There are a few real dangers associated with firing degraded ammunition. 

  • Ammunition that has oxidized is technically still relatively safe to shoot, but it will make your gun very dirty, leading to other complications during a day on the range.
  • When ammo is corroded, the structural integrity of the casing is likely compromised.  As a result, firing these rounds can lead to the case exploding and damaging your weapon or yourself.
  • When moisture has degraded the powder inside the case, it can lead to squib loads.  Squib loads are rounds that are underpowered and get stuck in the barrel.  A beginner may not recognize a squib round and be tempted to fire a follow-up shot, which is obviously a bad choice.  Very bad.
  • There is also the potential for a chemical reaction inside the case, which forms explosive crystals.  As the name suggests, these crystals will add extra “boom” to your boomstick:  probably more than you want.
Tips For Storing Your Ammo Properly

Tips For Storing Your Ammo Properly

As scary as firing bad ammunition sounds, there are fortunately ways to prevent ammo from going bad through proper storage.  Properly storing your ammo can extend its shelf life indefinitely. 

In fact, we have been fortunate to fire many weird and wonderful weapons, with the most recent being an old Lee Enfield 303 dated back to 1918.  That’s ammo from the second South African Anglo Boer War, and they shot fine.

1. Use Ammo Boxes

Ammo boxes have been a tried and tested method of storing ammunition for many years.  More modern options are plastic, which is also less vulnerable to the elements than metal. 

When looking for an ammo box, make sure to look for one that has a rubber gasket in the lid which will further keep your precious ammo stash separated from the nasty elements.

If you can’t find one with a gasket or already own one that doesn’t have one, then there is a pro-tip you can use.  Toss a few silica-gel packets (like the ones in packaging boxes) in the box to help absorb the moisture.  Even if your ammo box does have a gasket, this is still a good idea.

2. Vacuum Seal Your Ammo

An alternative, or even additional option, is to vacuum seal your ammunition.  This is not only a great option to keep it more protected from elements, including dust and dirt, but it also helps you keep your ammo organized.

Knowing how many rounds you put in a vacuum pack makes it easy to know how many cartridges you have left in your storage just from counting the packets.  Granted, the same goes for unopened boxes, but the boxes will take up more space.

3. Store Your Ammo In A Cool Dark Place

You will want to limit temperature fluctuations around your ammo storage as much as possible.  This means that the garage or attic isn’t necessarily the best option for storage as they generally aren’t as well insulated as your house. 

Your house may also be equipped with climate control, making it a better option for a storage site. 

It’s also great practice to keep your ammo out of direct sunlight exposure.  The sun is vicious and, with enough time, it will degrade all in its gaze of glory.  So, keep your ammo in your ammo boxes and perhaps give them space at the bottom of your wardrobe. 

Here is a handy video on ammo shelf life and storage:

Remember To Recycle Your Carry Ammunition

If you carry a weapon daily, concealed or open, you need to be aware that the ammunition in that weapon is along for the ride through dust, BBQ ash, beer spills, heat, cold, rain, sweat, and tears. 

It is strongly advised that you recycle or change your carry ammunition regularly.  Many would advocate for swopping the ammo at least once a year, with a preference of around six months. 

This is an excellent chance to fire the ‘old’ ammo in a practice session to keep you accustomed to how your carry ammunition responds.  If there is any ammo you own that you need to work without fail, it is your carry ammo.

Old Ammo Vs. Bad Ammo

A point worth making is that old ammo, especially well stored and kept ammo, is generally safer than plain bad ammo

By “bad” ammo, we are referring to the giant sardine can of super-bargain Second World War Russian ammunition you got from a suspicious online trader. 

Having fired cheap Chinese 5.56 ammo ourselves, we can tell you that is a little like playing Russian Roulette with yourself.

You’re probably better off buying old ammo at a deal from someone you know or a dealer you trust than you are firing unknowns through your precious firearm, even if it means that you have to check the old ammunition for warning signs before using them. 

Reloaded ammunition is also cheaper than new ammunition, but there are also inherent risks attached.  For example, if the back-yard reloader wasn’t paying attention, they could easily have over-, or under-loaded a cartridge, giving you a bad day. 


Ammunition can definitely “go bad” if it hasn’t been appropriately stored for many years.  Bad ammo can be unreliable or even dangerous in extreme cases.  On the other hand, Properly stored ammunition will outlive its owner. 

Ensure that you store your ammo in sealed ammo cases or boxes that keep it separated from temperature and moisture fluctuations.  It is also an excellent practice to change your carry ammunition at least once a year to ensure that you are always carrying good ammo that won’t fail you. 

Related Articles