I use zip lock bags to store 300 blk out and 5.56 and I note the quantity on the outside of the bag along with the load used. These re generlly stored in a ammo can either plastic or metal. The 308 go into plastic also and into open top tote pans. The 9mm go into re-purposed coffee cans and into the bullet boxes the raw bullets came in. Generally about anything that is clean and can be marked and stored.