[Greysard]

it is an interesting question, from a layman’s legal sense at least. Minors can’t purchase alcohol, for example, and it’s also illegal for adults to purchase and give booze to minors. An imperfect analogy, but that’s why I think it’s interesting.

I think the analogy is too imperfect. A minor cannot have alcohol, regardless of the method of obtaining it. This case deals with US citizens who have a right to own a gun, and can buy it themselves.

In essence, this is about government interference in private transfers of goods that both parties are legally allowed to own. The trick is that the right to own a gun is getting detached from the right to get a gun without some government agent making a note in your permanent database records. Subjects of California do not have this right, with exception of spouses.

[OneWingedShark]

A minor cannot have alcohol, regardless of the method of obtaining it.

I think you are incorrect here — or are you willing to allow the regulation of sugar, water, and yeast? (A la Wickard)
See homebrewing — note that their legal reasoning here is deeply flawed: if the 18th amendment gave the federal government the authority to regulate alcohol, then its repeal (by the 21st) makes all such laws invalid as they no longer have authority.

[longtermmemmory]

a minor can inherit an automobile even though they are too young to drive.