I'm hoping they seal well, I have been buying Harbor Freight plastic ammo cans when they go on sale for around $5/ea. They stack sideways in filing cabinet drawers. I wouldn't put that much weight in the cheap filing cabinets but I have bought several of the commercial fully suspended type over the years used cheap and they hold a fully loaded drawer fine. I also have some larger storage boxes but I like smaller boxes for more near term use and staging for later storage in bigger containers so I don't have to open the big boxes very often.
I have thought of going to vacuum packing but so far have not invested in the equipment. My Son went a step further by packing loose ammo with just the end of the box with the batch info in vacuum bags and then storing the bags in ammo cans, saves a lot of space.