Think of them for more than food.


Circa four years ago my girlfriend and I dabbled in using one of those vacuum food sealers for ammo, mags, etc.

Pros:

For loaded mags they seem to work great. We have a couple dozen mags vacuum-sealed and they are still just as tight as ever. These make great SHTF packs that you know are ready to go on a moment's notice but can stay sealed and corrosion-free indefinitely.

Cons:

Loose ammo doesn't do so well. The rounds never become really tightly sealed and this leads to small holes, edges tearing, etc. The sealed packages also flex too much if you have to move the ammo around occasionally, leading to more potential tears. The ammo also seals more or less "flat" making for difficult storage due to the package's footprint. We tried storing 100 loose rounds at a time and the package flattens out to about the size (but not thickness) of a pillow. That's too much if storage space is limited.


Conclusion:

For ammo I'd rather use surplus military ammo cans with the rubber gasket. For mags and other objects with a definite "one shape" it works great.