Properly stored ammunition can last decades.  There are times when ammo can be hard to find.   When shortages occur, people tend to stock up on ammo when they can get it.  This means that they need to store ammo for longer periods of time than they normal.  The main concern when storing ammo is its exposure to moisture.  Moisture poses a very real, very common threat to ammo.  A watertight container and desiccant stored in a cool location will provide excellent storage for any type of ammo.

When it comes to storing ammo, moisture is the main hazard to consider.  Ammo that is exposed to moisture can end up with damp gun powder.  When gun powder gets damp, the risk is that it won't be able to ignite and propel the bullet out of the barrel.  Without sufficient propulsion it is possible that the bullet could get stuck in the barrel.  Another bullet being fired before the damp round is cleared could cause the gun to explode.  Certain types of ammo can withstand exposure to moisture, some cannot.  Enough water could get in to liquefy the gun powder, rendering it useless.  Moisture could also corrode the primer caps, which could make them ineffective, even dangerous.

Protecting stored ammo from moisture is easy.  A watertight container combined with a desiccant, Silica Gel for example, stored in a cool location should provide adequate protection against moisture.  A container with a watertight seal will prevent moisture from humid air to water from flooding from getting into the container.  Storing the containers on a shelf that is elevated off the ground is also a good idea.  Military ammo cans have rubber gaskets to create a watertight seal.  The use of a watertight or water resistant safe can also provide appropriate storage for ammo.  Even plastic tubs, like those that cat litter or bulk laundry detergent are sold in, can be used for ammo storage.

Placing a packet of Silica Gel in with the ammo will remove the excess moisture from the air inside the container.  The moisture that is in the air could potentially condense on the metal primer caps and corrode them.  Silica Gel will absorb the moisture before it can condense and cause damage.  There are several sizes of Silica Gel packets available made from any of three materials.  The size of the container will determine the size of packet that is appropriate.  When the Silica Gel becomes fully saturated, it will no longer provide protection against moisture and will need to be replaced or reactivated.  A cotton, paper, or Tyvek® packet should be used with a humidity control card to monitor the saturation level.  Perforated plastic packets with Indicating beads is another way the saturation level of the Silica Gel can be monitored.