We have a rather large collection of weapons….handguns, rifles, machine guns. We have alot of stored ammunition in the house. Much of it in surplus military cannisters. (ammo belts, 308, ammo for water cooled weapons, ammo for m60, sten etc) I am concerned that after years of storage that this ammo could degrade and emitt toxic chemicals that we are not aware of. Could you advise? I have been told that it is unlikely…but i still have concerns.
There’s two questions here I want to address. First is the implied question of how long military surplus ammunition lasts. Second is the explicit question of if degrading ammunition can give off harmful chemicals.
As for the first question, the shelf life of military surplus ammunition depends on a number of factors. The most important factors are whether the ammunition was stored in a cool, dry place and whether it was exposed to ammonia, as these will corrode the brass case.
The good news is that most of the military surplus ammunition was sealed in watertight cases following manufacturing.
The best example of this watertight case is the “spam can” that surplus 7.62x54r ammunition (and 7.62×25, and 5.45×39…) comes in. Russia (well, the Soviet Union at the time) was very concerned about possible future invasions, and so designed their ammunition cases to be cached away in every nook and cranny of the country, waiting to be used to fight back the Nazis once more. The benefit for us is that the ammunition is no longer used in the same quantities by the Russian army and available for civilian sale, and thanks to these spam cans the ammunition is in perfect condition even 50 years after it was manufactured.
In theory, the shelf life for modern ammunition is longer than we will ever live to see. Ammunition produced during WWII is still being used by U.S. combat troops in action today, and with modern advances in smokeless powder manufacturing the rate of degradation is much slower than it used to be. However, care should still be taken with older ammunition as smokeless powder does indeed degrade over time (however slowly).
Not all military surplus is so well preserved, however, as the lead picture illustrates. Some poorly stored ammunition may have corroded over time, and the best way to check if your ammunition is good is to visually inspect every round of ammo you put in your gun, paying extra special attention to the primers. If there is any suspicious discoloration, bulging or corroding on the outside of the cartridge then it should not be used and should be discarded. Usually the local gunsmith will be happy to check out any ammunition you have questions about, something I highly recommend taking advantage of. Then again, the old “long-ass string tied to the trigger and hiding behind a tree” method works too.
As for the toxic side of things, there are some hazardous materials in ammunition. The biggest hazard comes from lead, specifically the rather large glob of it on the front of the cartridge (AKA the bullet). The primers also contain some small traces of hazardous elements, but under normal conditions none of these materials should become airborne or even leave the confines of the storage container in which they are housed.
The biggest concern comes from within the cartridge itself. The gunpowder is usually composed of some mixture of collodion (an old developing solution for photographs), nitrocellulose (common explosive screened for at airports) and nitroglycerin (see Alfred Nobel), all highly reactive compounds specifically chosen for their ability to quickly burn and produce gases. Smokeless powder has a tendency to degrade over time, and after a long enough period it will actually produce a purple or reddish vapor which indeed is very toxic to inhale. The good news is that if the ammunition is in tact and the powder is not loose then the vapors will be trapped inside the cartridge, and the better news is that even if that vapor escapes the cartridge the surplus canisters will trap the escaped vapors.
So, in short, degraded gunpowder can indeed give off toxic vapors. But it takes years and years for the gunpowder to degrade, and as long as the ammunition is stored in a cool dry place it should last for decades to come. I’d recommend only opening the older canisters outside in the open air, but anything made within the last 50 years should be golden.
The chances of toxic vapors leaking out of your older ammunition are remote. But, just to be safe, I wouldn’t keep that 1918 vintage canister of .30-06 ammunition under the bed. (All of my ammo is stored on the other side of my apartment near a ventilation duct when not in use.)