It is important to note not to store you ammunition longer than necessary. Now, what do we mean by this? Rotate your ammunition whenever possible. So, instead of storing 5000 rounds of 5.56 or .223 for 10 years, mark each ammo can with the date you acquired the ammunition and the ammunition type. As you acquire more ammunition, of equivalent type, use the oldest ammunition first. This provides you a method of keeping your ammunition stock as fresh as possible. Of course, there is more to ammunition than caliber. You will need to mark your ammo cans with all the appropriate information. Most shooters are not going to open a case of 62 grain M885 green tip for target practice and store cheap 55 grain Wolf 5.56 ammunition. They both might be 5.56 ammunition, but they are very different in terms of performance.

Next, keep the humidity out! If you are storing ammunition in a less than ideal location, humidity will likely be your biggest enemy. The DoD stores ammunition in non-environmentally controlled warehouses for decades. If you have good ammo cans and pack your ammo well you can easily have your ammunition survive very long term storage. During Desert Storm (that was 1990-1991) Soldiers were issued 5.56 ammunition that was manufactured at Lake City (LC 67) (manufactured in 1967) that performed well showed no signs of degradation. You can easily store your own ammunition by ensuring the humidity inside the ammo can is low. The key to success is to lower the humidity in all the packing material before sealing the your ammunition in an airtight container such as an ammo can. If you are storing loose ammunition this is not really an issue since there is nothing to trap humidity, but air. If you are storing your ammunition in cardboard boxes inside the ammo can you will need to get the humidity out of the cardboard before sealing the can for storage. The easiest way is to use a dehumidifier, you probably have on inside your gun safe to protect your guns. Placing the ammo and container (unsealed and open) inside the safe several days will draw the moisture out of all the packing material to ensure you start with the proper humidity conditions. Next take a few new desiccant packets (1/2 or 1 oz packets) and place them in the ammo can. Finally, a worthy addition to the storage container is a humidity sensor card to provide a quick visual inspection as you spot check your ammo. All you need to do now is seal the ammo can and it should give you years of successful storage.

Now that you have your ammunition sealed and stored you will need to spot check it every 12 to 24 months. The key point to remember is typically winter provides lower ambient humidity and summer is a much higher humidity, at least here on the East Coast, so adjust your checks to correspond with a low a humidity season for your area. This will decrease the impact the your check will have on your interior humidity. If you placed the humidity sensor card in the ammo can, your checks will only take a few second. Simply, inspect the card to ensure the humidity is under about 30%, remove the existing desiccant packets and replace with new desiccant packets. The cost of desiccant packets for a can of ammunition should be less than $1 and the humidity sensor card can be found for less than $.50. This is really a trivial amount to protect the typically hundreds of dollars of ammunition that is stored in one ammo can.