By storing in vacumn bags, then stacking those in a bucket (square buckets are better, round is hard on stacking) or a tight-locking storage bin, adding some silica salt packets, and flushing with CO2 ...
Oh, and storing in a "cool dark place"; you can get really good storage time.
A packet of silica in with your vacumn bags is even better.
Moisture = corrosion. Corrosion = bad ammo. Control the moisture, and the ammo stays happy.
Chemical breakdown of the powder is a different story. But if you're purchasing good quality, well-known brands, then it shouldn't be too bad.
Food is more of a PITA, but all of it should be *ROTATED*, which is the biggest PITA of any good storage system. Especially if its...oh... burried?
