Not sure about that.
Then it would be a straw purchase to buy a gun for your kid if he's under 18 for a rifle or 21 for a handgun.
Which from what I understand is not the case.
You just have to buy a gun for someone who can legally OWN it, not purchase it, i.e. not a felon.
My understanding, and correct me if I'm wrong, is that you can legally own and even carry (albeit with a LTCH) a handgun at 18, you just can't "buy" one until you're 21.