[hga]

And that is how I quickly explain ORM-D (https://en.wikipedia.org/wiki/ORM-D) class items like small arms ammunition, which of course is allowed to be packed in small quantities in individuals' checked luggage: things that aren't particularly dangerous by themselves, but if in a plane's cargo hold in sufficient quantity, could accelerate a fire beyond the capabilities of those fire suppression systems.

Whereas few overly worry about shipping 1000+/- rounds by ground, except e.g. the movers that just moved me to my new home, they really can't afford to play the game of numbers with the few trucks they have (no batteries, or liquids (which could make a schedule breaking mess), either).

Big enough high energy batteries on planes, or too close to my skin ... those give me the heebie jeebies....