How Long Will Ammo Last?
by Kirk Lawson
Right now ammunition is in a "seller's market." Ammunition manufacturers are cranking out as much as they can, as fast as they can. And pretty much every last drop of it is selling within days.
Some people are new gun owners and trying to buy ammunition in order to supply their new guns. Some are more experienced owners and are trying to maintain their existing supplies while shooting. Some are trying to build up a personal emergency supply in case shortages continue long term or get worse; like having a couple extra gallons of gas for your lawn mower. And, of course, some are trying to buy up supplies of ammunition at the store then sell them online or elsewhere at higher prices to people who couldn't get supplies at the gun store. [Parenthetically, most gun stores hate this practice because it makes it hard for them to keep their customers happy with a small number of people buying all of the ammunition and then reselling it at higher prices. Consequently, many gun stores are rationing ammunition purchases.]
But for new shooters and the less experienced trying to build a small stock, the question often comes up, "how long is this stuff good for, just sitting around?" It is a valid question. After all, like the gasoline example, people have to put a stabilizing compound in their gasoline to keep it from going bad. So how long will ammunition last before "going bad?"
The good news answer is basically: Forever.
The chemicals used in the smokeless powder propellant is usually the most vulnerable to age. It can break down over time. But all modern smokeless powders are engineered so that they are very very stable, and have been so for a century or more. Ammunition from WWI and before is often still good and in shootable condition. What is the enemy of the powder is typically heat. Excessively hot conditions can accelerate the process of the powder breaking down. Unstable powder is unpredictable. It may not burn at all, react very weakly, or burn far too quickly and create dangerous over-pressure. So, generally, do not store you ammunition in places where it gets excessively hot. While your non-air-conditioned garage can get uncomfortably hot, it is usually OK, but your attic, where temperatures may exceed 150 degrees F., is hard on the powder.
The metals in the cartridge are no different from any others. Brass, copper, and lead can all oxidize. So it is important to keep the exterior of the cartridge clean and dry. Store it so that it is shielded from excessive moisture, and even outright wetness. If the cartridges are handled (touched with your fingers) then they should be wiped down with a clean, dry (not oiled) soft cotton cloth. Human fingerprints are acidic and salty. They can etch metals and cause them to corrode. It is no unheard of to find older ammunition where the brass case is green and scaly or the exposed lead of the bullet is white and flakes off. These are corrosion and would make the cartridge unsafe. But a clean, dry, cartridge will not corrode like that.
So, to maximize the life span of your ammunition, store it in a cool, dry place. Basically, if you would feel comfortable sleeping there, your ammunition probably will too.
Some owners like to purchase "ammo cases" specifically made for storing ammunition. They are usually steel or plastic, open at the top, have a water proof seal, and a carrying handle. Some will even put a fresh descant pack in the box, though it may not strictly be necessary.
[Surplus military steel "Ammo Can."]
[New manufacture plastic "Ammo Can."]
We do have one other thing to discuss here about safe storage of ammunition. It should be stored in a manner that unauthorized people do not have ready access to it. You will have to decide how that works in your home. For instance if you do not have children in the home and do not ever have visitors, then your entire home is a "storage container" to prevent unauthorized access just by putting it in your closet and locking your front door. But if you have children, or even if you have well trained teen or adult children, but have visitors in your home, then you need a way to deny access. Some of the "ammo cans" discussed above have a lock hasp for a traditional removable lock. Some people choose a sheet steel locker for guns and ammunition typified by the Stack On (tm) brand. Some people have full sized safe and store both guns and ammunition in there. Some people get creative and may use a locking file cabinet, actual refrigerator with a lock, or a cabinet with a key lock on it. In any case it is your responsibility to take steps to prevent unauthorized people from accessing your ammunition.
[Stack On (tm) brand sheet steel Gun & Ammo cabinet.]
[3-Drawer filing cabinet.]