I usually keep mine loose in 30 cal cans. Any larger and they would be too heavy to be practical.
For long term storage I silicone the rubber gasket, displace the oxygen with dry ice. Try not to touch the rounds with your bare hands.
The main ones I keep on hand are .308, .223, 9mm, and .45
I do keep a few loaded in mags. I am trying to do the leap frog method of buying a case, shooting half, buy a case, shoot half you get the idea.
I wont disclose how much I stash, more than some here but trying to catch up with the others.