Very true--a wilderness of differing rules, and it gets confusing trying to understand them all, Jn. When I was a kid, working in a convenience store during high school, it was illegal to sell rifle/pistol cartridges on Sunday morning, but shotgun shells were OK. (Maybe the lawmakers thought the ducks had it coming.) ;-) In my college years, at my parents' little vacation cabin, you had to drive to the next county to buy beer, back at home, if you were 18 you could get a bottle of rum at gas stations, and where I live now only the state is permitted to sell booze. If you pick 20 places you've got 25 different rules. How do we deal with the differences between places? Do we even want to, or should local opinion decide? If a gunman is holding off police by threatening to shoot himself, is that a hostage situation?
We've got way more questions than answers, and your post brings up a lot of them. I *will* state without any reservation or any modifiers that TV newspeople who call a semi-automatic firearm "an automatic" weapon should be kicked in the tail until they understand the difference. ;-)