Ammo Oracle

Introduction

Probably overkill, unless your hyperparanoid.

Most good M193 ammo is sealed in any event. (You can sometimes see the sealant around the primer).

It might be a good idea if you plan on storing the ammo in a very moist environment and don't trust the seal on your ammo can, but those vacuum food packing machines are very expensive- you'll probably spend more on the special bags anyhow, and ammo cans are awfully cheap. It's much easier to just buy another ammo can--they are airtight as long as the seal is intact, drop some desiccant in and you'll be ready to go.

Trust us, your wife is about to lose it over all the ammo you're hoarding in the basement already. Spare yourself her wrath and pack it out of the way somewhere in nice orderly stacks of ammo cans instead of using her new toy.

Opinion: It's probably a good idea to inspect the seal on your ammo can. Look for cracks, damage or signs of dry or brittle rubber. Clean off any debris carefully before closing your cans. If you are especially paranoid or planning on multi-decade storage you might want to treat the seal with some rubber preservative.