Long Term Shelf Life of Ammo

[SandRoad]

i like to seal ammo with a vacuum sealer and then into a ammo box it go's if the ammo is not in sealed cans that is(most surplus is) this stuff will last in a flood

it does get really humid down here

Vacuum sealing is great short and medium term storage, say 5 to 10 years, under good conditions.

One thing is that plastic isn't very good at keeping moisture out in the very long term (20+ years). Water molecules diffuse through materials amazing well.

Let me give you an example. Years ago I was talking with a scientist/engineer who was in charge of quality control for implantable pacemakers.

They had nuclear powered pacemakers with a power supply that would last more than 20 years, however there was a problem, water molecules would get into the electronics and bugger them up. The electronics were encased in epoxy, inside an electron beam welded stainless steel case, encased in silicone.

 

[Andurp]

I bought a crate of Chinese 7.62x39 made in 1964 from Tradex and the wood crate had water stains all over it and the spam cans were literally such hunks of rust that all I had to do was whack them on the top with a hammer and they fell apart. I was quite worried all that water got into my ammo.

If it actually did, it didn't seem to matter, as all 1440 rounds of ammo went bang and shot quite well, too.