Please reconcile this with a private sale where ownership clearly changes, but no FFL or transfer is required.
At least here in TX, I can sell or gift with zero paperwork and still be fullh legal. The only issue I see here is that age to possess and age to purchase may not be the same . . . and, by your statement, every kid that ever got a .22 for christmas would be a criminal . . .
A bit of research telle me that to buy a handgun, min age is 21 from and FFL, but only 18 for a private sale. For long guns min age to purchase from and FFL is 18, and no minimum for a private sale. I also see that Fed law prohibits handgun ownership under 18, but sets no minimum for long guns . . .. So, based on Fed law alone, if he bought the rifle privately in IL, he was legal for both purchase and possession, and there would be zero requirement for an FFL in that process.
What I *don't* know is how much more restrictive Wisconsin may be . . .
Your cite may apply, but it cannot be certain, since so much is unknown about what happenrd on which side of the border. (and some might consider orc hunting a "lawful sporting purpose" (and frankly, I am amazed that 'sporting' is stated, and not just 'lawful purpose' . . ))
We also don't know if, in the case he was not the owner, if the owner was also present . . l just hope this kid doesn't get boned on a technical detail, while overall doing the right thing. The good news is that iny Fed charge is out of the hands of the bought snd paid for local dimmie prosecutor, and could conceivably be considered for a Fed pardon, depending on the finsl details.