Does Ammo Go Bad - Ammo Shelf Life & Storage

Does Ammo Go Bad? Ammo Shelf Life & Storage

Ammo is the essence of guns. People often store them for emergencies, so they may not be in use for long. Therefore, a common question that revolves around the minds of gun owners is – “How long does ammo last?” or “Does ammo go bad?”

The ammo does not go “bad” per se, but the powder and the primer lose their potency over time. Initially, the life of ammo depends on the manufacturing technique and the quality of primary components. After getting manufactured, it mainly depends on factors like place of storage, temperature, moisture, and exposure to air.

The key factors behind the degradation of ammo are –

  • Use of black powder while manufacturing
  • Using bullets with exposed lead
  • Exposure to a high temperature
  • Keeping it in a moisture-rich area
  • Frequent exposure to air
  • Use of oil or cleaning solvent.

Measures for improving the shelf life:

  • Keeping it in a cool, dry, dark place
  • Use a vacuum sealer
  • Tagging; using the first stored ammo first
  • Frequently rotating the ammo in a concealed carry gun
bullets ammo old

Material Used

The primary thing that determines the life of the ammo is its material, especially what the primer, the powder, and the case are made up of.

The chemical composition of powder may vary from manufacturer to manufacturer. But, it generally includes nitroglycerine and nitrocellulose, which are potential reasons for its degradation. If the ammo is rich in these nitro components, there are high chances of its shelf life being considerably less.

Earlier, black powder – which has a relatively shorter life span – was used as propellant. Today, however, modern ammo uses smokeless powder, which has a considerably longer life span.

Further, ammo having a steel case is more vulnerable to corrosion in comparison to one with a brass case. And a bullet having exposed lead is more prone to lead degradation than those with full metal jackets or those that are brass-lined. It is simply because the former comes in contact with oxygen frequently.

How to assess degradation: a violet or scarlet-colored gas from the canister is an indication that they have come in contact with the outer surroundings, and the primer has degraded substantially.


rusting ammo

Humidity is another principal reason behind the degradation of ammo. Ammo stored in a high humidity area culminates in moisture seeping into it, turning the primer and powder damp. As a result, the rounds become less effective and sometimes don’t even fire, called a “misfire”.

Also, moisture causes corrosion to the exterior of the cartridge (the case and the bullet) as well.


hot ammo torch

The temperature is also one of the significant aspects that impact the shelf life. High temperature or extreme heat increases the interaction of air with ammo resulting in its degradation.

As soon as the powder is put in the ammo, it starts breaking down. Although it is a very slow chemical process that takes many years to complete on its own, it gets accelerated at higher temperatures. The reason behind this is a simple scientific theory – the higher the temperature, the faster the chemical reaction is. (The “reaction” here is the deterioration of the primer and the propellant.)

Also, some jacketed loads and lead bullet loads include a grease groove on the bullet that melts out if the ammo is put under a very high temperature.

Besides, a place experiencing high fluctuations in temperature (above 20 degrees) too makes the cartridge susceptible to degradation.

Air Exposure

vacuum seal ammo

Apart from the factors discussed above, exposure of ammo to air also impacts its life span. If ammo comes in contact with oxygen for a substantial period, a chemical reaction starts inside the ammo, affecting its life adversely.

The hunters and outdoorsmen are more susceptible to this, and hence, their ammo has a relatively shorter life span.

Use of Oil or Cleaning Solvent

The ammo also gets harmed when stored near an oil or any cleaning solvent. Or in case any such substance is used to wash the outer surfaces of the cartridge.

Exposure to oils or cleaning solvents neutralizes the priming compound and makes the powder void, putting the ignition process at a standstill when the trigger is pulled. Moreover, these substances also affect the brass of the case adversely.

Measures for Improving the Shelf life

Keeping Away from Moisture

silica gel

The first and foremost step for a long life of ammo is to keep it in water-tight boxes to ensure that moisture stays out. The best way to do so is to put the ammo in its original box and use the vacuum seal. Putting the ammo in sealable food containers is another good option.

A damp basement must be avoided for storing the ammo. In an area with high humidity, one can opt for a humidifier, which not only improves the life of ammo but also has other household benefits.

Using silica gel packets inside the sealed bags can be instrumental in removing the residue moisture.

Storing at a Cool and Dark Place

A temperature near 70% with a humidity of 50% is an ideal situation for keeping the ammo.

High heat accelerates the chemical breakdown and degrades the ammo. Therefore, it is advisable to keep it in cool and dark conditions with minimum exposure to sun rays.

Putting ammunition in the trunk of a car in hot summer months must be avoided at all costs. 

The garages should be avoided too, as they not only have safety issues but also the uninsulated ones can be very hot, which is bad for ammo.

Tagging and Rotating

case ammo

It is better to keep the ammo in its original case with its month and year of purchase marked, and then use it as per the storage date (that is, the ammo stored first, be used/fired first) to keep it as fresh as possible, with minimum disruption.

In a concealed carry firearm, one should rotate the ammo a few times within a year since continued exposure to the air or moisture, indentations from the feed camp, and excess lubrication can substantially harm its chemical substances, especially the primer and the powder. Further, one should practice regularly with such a gun to keep its ammo fresh with its lethal potential.


Extreme temperature, humidity, and air exposure are the core factors which either individually or jointly deplete the lifespan of ammo. If one keeps them with the utmost caution, the modern ammunition has a much longer lifespan than ten years (as usually guaranteed by the manufacturers).

Chris Green

Chris has always had an adventurous soul, and his love for the outdoors eventually led him to become a professional life skills advisor. He explains a multitude of different topics ranging from disaster preparedness and wilderness survival to self-sufficiency.

Recent Posts

Can You Eat Wild Boar Meat? Safety and Risks

Raw Chicken Left Out For 8 Hours: Still Safe?

Can You Eat Opossum? Risks & Correct Preparation

Can You Eat Mahi Mahi Raw? Safety and Precautions

Can You Eat Beaver? Health Considerations & Risks