[marktwain]

but it is illegal for a minor to own a handgun.

It depends on the state.

Most states it is not illegal for a minor to own a handgun, but it is illegal for them to carry outside the home or family property. There are often other exceptions.

There are legal differences between ownership, possession, and carrying, and where carrying.

[jurroppi1]

Pretty sure you’re going to run into Fed law issues...

It’s and old WaPo article, but still, there is at least a link to the “exceptions”:
https://www.washingtonpost.com/news/wonk/wp/2014/08/27/in-30-states-a-child-can-still-legally-own-a-rife-or-shotgun/

Minimum Age for Gun Possession: Subject to limited exceptions*, federal law prohibits the possession of a handgun or handgun ammunition by any person under the age of 18.15,16 Federal law provides no minimum age for the possession of long guns or long gun ammunition.

*Exceptions: Federal law provides exceptions for the temporary transfer and possession of handguns and handgun ammunition for specified activities, including employment, ranching, farming, target practice and hunting.

I keep finding the same info on several sources (another would be findlaw).