I don't use but a few calibers of ammo and what I use is all stored in old ammo cans,each of which hold X-amount of given caliber....so mostly, "taking inventory" is merely a matter of looking at labels, counting how many cans I have of each, and then doing a bit of simple math in my head.
Other than that, once a can is opened, all of the boxes from that particular can get transferred to the "using shelf", the can itself get's turned around so the label don't show, and that particular can doesn't get counted again until it's re-filled with new "stock" and turned so's the label shows again.
As for the boxes on the shelf, I don't even bother about "how many". Reason is, it's perty-easy to know from a glance when it's getting close to time for opening another can.
But that's just me, I like keeping things simple.
DGW