Vacuum sealed ammo

It would depend on the ammo. Smallbore rifle shooters avoid allowing their ammo in unpressurized airplane cargo areas because the lowered air pressure screws up their accuracy.
 
I have given it thought; but concluded the practice could be viewed as overkill.

The only ammo I store is stuff like MilSurp, and I have opted to use GI-type sealed ammo cans for its storage. I have seen some very old MilSurp come out of such containers looking brand new, and there wasn't any desiccant involved.

The same is true of ComBloc MilSurp 7.62x54R packaged in their common Spamcan containers, no vacuum, no desiccant.

Greg
 
Im like Greg, i just use ammo cans for ammo i will be storing for awhile. I toss in a couple small desiccant packets for good measure and i keep the ammo in the closet so it has a pretty stable temperature and moisture environment. Ive gotten mulsurp ammo stored in just the cans (greek 30-06) and it has been just fine.

The desiccant packets are dang cheap too so doing that vs buying the vacuuming equipment, financially for me, makes more sense
 
Cartridges typically have an air pocket inside because they are not totally full of powder. If you put the outside under vacuum, the inside wants to pressure equalize. It could unseat the bullet a little to compensate.
 
I've used my FoodSaver and vacuum packed most of my .45 & 9mm ammo years ago. Some has bled vacuum off but most has held and I've never had a problem with any of it when taken out to use. I have yet to find one that the bullet has pulled out on.

As has been said, it's probably overkill....