My thanks to Sipsey Streeter es for forwarding these pics of his packaging of 5.56 NATO (note that it's in bandoleers and stripper clips) for long term storage using food vacuum seal bags. This is an excellent idea, especially for anything you are going to cache underground.
These are the current-issue 4-pocket M16 bandoleers (the white thread you see is a pull string that opens the pocket up, making it deeper so as to accomodate a fully-loaded thirty round magazine). Thus each bandoleer has 120 rounds in it. Or 720 rounds in an M2A1 "fifty cal" can.
"The main point I was getting at was to vacuum pack your ammo to keep air and moisture from getting to it as an extra precaution for long term storage."
"And if you do it, all sharp points have to be covered up because it will poke through the plastic and ruin the seal."
"6 bandoleers can fit in an M2A1 can."