Our gun laws are more permissive than a lot of places, but still an absolute mess.

Federal laws define anything under a 16" barrel as a short barreled rifle- SBR. That’s a colossal no-no and a felony. That is enforced.

The other big thing is that one trigger pull = one round fired. If it breaks that rule, or fires from an open bolt the ATF considers it a machine gun and those are pretty tightly restricted. You can’t manufacture more machine guns for the civilian market, they have to be grandfathered in from before they were banned.

There’s tons more whacky Federal stuff- like how they treat suppressors. Federal laws have nothing on state laws though. Man does that get confusing when your gun is absolutely fine in Nevada but is a turbo-crime in California. God forbid you bring a thumbhole stock into California. And then there’s concealed carry permits- a lot of places it’s illegal to carry a handgun concealed with a permit. But the permits are all state issued and whether they’re valid in other states is entirely fucking random.

TL;DR: we get a lot of shit for having lax gun laws- and we do- but they definitely exist and navigating them can be a gigantic pain.