Mil Surplus ammo and sealed cans...really sealed?

[Southern Shooter]

Some of the military surplus ammo comes "sealed" in metal cans. Are these cans airtight or are they just designed to hold the ammunition and keep it from getting damaged??

If they are truly "sealed" and airtight, would that not preserve the ammunition for an indefinite time? It takes air to cause decomposition in materials...right? And, if there is no air then the ammunition should keep for a long, long time. Is that thinking correct or am I mistaken there? Or, does gunpowder just lose its "fire" with time even if there is NO oxygen in the mix?

Thanks

 

[geronimotwo]

for no oxygen wouldn't they need to fill it with an inert gas? co2, or nitrogen?

 

[Spitzerbullet]

I've opened twenty year old spam cans and found paint inside that was still wet. I certainly believe that they are sealed and possibly nitrogen filled first.

 

[Slamfire]

I was watching an episode of History Channel, and they were diving on British BattleShips that had been under water in the Dardanelle’s since 1915 (or so). One diver brought up some cannon cordite, which was as thick as a clothes line, and used a cigarette lighter to get the stuff to burn. Seems to me that gunpowder will last a long time, even under water. From what I understand about gunpowder is that the longevity of the stuff depends on how well it was made to start with and how it was stored afterward. I had military pull down powder that degraded and turned red. Someone said it was improperly washed. Well whether it got a good shower at birth, I don’t know, but it was improperly made. I will assume that properly made gunpowder will last a very long time. But it is a plastic. Which means that it will degrade on exposure to light and heat and the corrosive stuff in the air. Car paint is a plastic, we have all seen that stuff fade, turn chalky, or just chip off. Thermal cycling probably will degrade it, but I really don’t know if seasonal temperature cycles is hard on gunpowder.

If you get water in contact with the brass you are definitely going to get corrosion on brass. Air also has sulfides, nitrates, and other pollutants in it. Nitrates cause “season” cracking. Canned air may run out of pollutants, but I really don’t know.

I really don’t know what degrades primers. I have shot estate sale pistol primers that dated from the 60’s. They all went bang and chronographed velocities were consistent with new ones. About 1985 I purchased 700 primed cartridge cases of RA54 30-06 brass. Every primer went bang. It had been stored well as the brass cardboard boxes were not even faded. The brass is on its fourth reload. Good stuff.

You know the military demills ammunition. They store the stuff in ammo cans, in bunkers, and they get rid of it after a time. There has been a whole bunch of Vietnam era brass on the market from demilled ammunition, maybe the stuff starts falling apart after 40 years. The WCC69 brass I bought was all good.

 

[Dave Markowitz]

The spame cans I've opened have definitely been airtight. As soon as I used the big can opener to punch a hole in them, I heard the hiss of air going into or comng out of it.

 

[Niner]

Sealed doesn't necessarily mean the ammo is particularly good. I got a sealed can of 7.62x54r from some communist block country that had about every other round with variable rim thickness that made chambering the rounds difficult to impossible. The ammo was preserved just fine....just it was not any good on the day it was made...unless maybe you had some other kind firearm other than a bolt action M91 Nagant to shoot it through.

 

[MilsurpShooter]

It all depends. You're in better shape storing a sealed spam can of 8mm ammo then you would be storing some cardboard boxes of it. Again, the air plays a factor in corrosion but so does heat, cool dry place, sealed spam can, yeah probably keep for awhile. At least I'm hoping. I'm sitting on about 8 sealed cans now, 4 Yugo 8mm and 4 Russian 7.62x54. Those are my Zombie reserves

 

[Southern Shooter]

Bulgarian Mil Surplus

I am also hoping that such "sealed" ammo keeps for a long time. I picked up 3 tins of Bulgarian 7.62 X 54R ammo. I opened one tin to take to the range. The stamp on the brass shows a 1952 production. It looks to be in GREAT shape. The ammo that is open I will keep in a very dry and cool location. I wonder under those conditions how long the opened 1952 ammo will last.

 

[shermacman]

I have boxes of 30-06 ammo for my Garand, hand packed in clips by the South Koreans in 1973. That means the ammo is now 33 years old, at a minimum. It shipped in surplus .50 cans that are not air tight. They fire every time!

 

[kfranz]

I wonder under those conditions how long the opened 1952 ammo will last.

Longer than you will.

 

[Ad Astra]

The tinned boxes the Yugo '50's 8mm come in is far from airtight- dings and the weight take care of that.

To repack in American ammo cans is best- you know they're moisture-tight if the seal's good.

Is a round itself airtight? I dunno.

 

[JonB]

Mine was selaed...tight

Just opened a 800rd can of 7.62x54r - Czech silvertip. That can was a bastard to open, but all the rounds I looked at were in great shape. Also opened a 300 rd tin of same caliber - just Bulgarian 182 gr heavyball.

From what I saw those cans are made to take some environmental abuse without compromising the contents. Now if it every warms up in SD enough for me to go shoot all the shiny new ammo......

 

[roo_ster]

Therer are whole DOD facilities that look at this issue: how to keep munitions (& other stuff) good-to-go while in long-term storage.

Sealing it up is only one part of the deal. It also helps to keep the temp nice, constant, and relatively low. Also, keep the salt spray to a minimum.

Sealed up ammo that is in the uncontrolled climate of a metal cargo ship traveling about the ocean from the tropics to near the antarctic circle won't last long. The same ammo in a "dark, cool, dry" climate controlled warehouse will be good for a very long time.

 

[byf43]

I've opened case after case after case of 'sealed' LC 69 and LC 72 M2 Ball.

The cans were tightly sealed. The ammo looked brand new and every one fired by the High Power Shooters went 'Bang!'

I've opened a few cases of Yugo '70s production 8mm Mauser ammo and it looked like it had just been packed.


Sealed???? Apparently.

I agree with storage temps, humidity, amount of light, all play a role in ammo 'freshness'.