I also store mine in GI ammo cans.
We took 4 ft of water in our walk out basement during Irene and I only had one can leak - and it was missing 2 of the 3 hinge pins.
Desiccant really isn't needed unless you packaged it under very moist conditions, AND live in an area where you get very cold temps that might cause the small amount of moisture in the small value of air in the can to condense. Even then it will primarily condense on the sides of the can as they are exterior surface that cool first), not the ammo, if it's boxed.
Inside the can I usually store it in MTM or similar 50 round boxes, and those are what I take to the range.
However on large lots of a couple thousand rounds where I run out of boxes, I'll dump the excess in 50 rounds groups in a zip lock freezer bag, squeeze out any extra air, then store the bags in the can. You can easily get over 1,000 rounds of .38 Special in a .30 caliber can with that method.
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I store my precision long range rifle loads in 50 round plastic boxes base down/bullet up with a piece of open cell foam rubber cut to fit in the lid. It protects the points and preserves the OAL even if you drop the box.
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My 5.56mm M193 clone ammo gets stored in 10 round stripper clips in 120 round bandoleers that are then stored in .50 caliber ammo cans - 840 rounds per can.