For the newbies, shot shells used to be bulk packed in cases of 500 (20-boxes of 25 shells -- 5 wide by two deep by two high). I don't recall if it was in the late 1980s or the '90s when they started making flats of 250 shells that were only a single layer high. IINM, the change was made to comply with revised shipping regulations.I bought a case or a flat, or, whatever they're called…