Black powders guns, whether antique or reproduction, along with air guns, regardless of power level, aren't regulated by federal law in the US either: although state and local law may say otherwise.

My hometown of Philadelphia, for example, completely bans the sale and possession of air guns and BB guns.

Ironically, the City of Philadelphia is located in the State of Pennsylvania, which is not only a "shall issue" state for concealed weapons permits, but also has a pre-emptive law, preventing its municipalities from regulating firearms.

But since airguns aren't "firearms", as defined by Pennsylvania law, the pre-emptive law doesn't stop Philadelphia from banning airguns.

So if you're a law-abiding adult resident of Philadelphia, you can get a permit from the state enabling you to legally walk the streets with a 15 shot 9mm under your coat: but you can't legally have a Daisy Red Ryder in your closet.

You figure it out!

Jim