What if the transferor and transferee both live in Ohio, but are in another State at the time of the transfer?
Well understandably there's probably not much case law on this subject.
For us to know what would really happen these things would have to occur.
1) the 18-20 year old would have to find someone willing to sell them a pistol, who resides in Ohio but is willing to drive across the state border to do it
2) such sale actually occurs
3) the 18-20 year old goes and does something stupid with his pistol or while carrying said pistol that gets him investigated by police
4) 18-20 y/o tells the police or prosecutor who sold them the pistol
5) the police/prosecutor determines that they have the ability to charge the transferror with something and that it's worth their time to do so.
now here's where it branches, the prosecutor can
A) attempt to prosecute under Ohio law, which would be difficult since the transfer occured out of state
B) he can contact the prosecutor/law enforcement in the out of state city or county in which the alleged transaction occurred and ask if they have any laws that the transferror can be charged with violating, AND that said agency(s) believe that to be a profitable use of their time and resources
C) contact the feds and see if they're willing to try a new interpretation of the GCA
6) one of those prosecuting agencies takes the case to trial
A)trial court agrees to put it on the docket and take it before a jury, AND no appeals court rules first on the possible legality
B) trial court dismisses charges or an appelate level review decides there is no basis on charges
(I)prosecuting agency appeals, such case now drags on for years
(II) prosecuting agency drops it, no charges stick to the transferrer
7) trial outcome
A) not guilty, nothing happens to transferrer
B) Guilty, standby for appeals
After 7(A) occurs this will become one big cluster-you-know-what...
Therefore with all these variables on my flow-chart, I think we'll never know exactly what could legally happen, so many unlikely things have to occur for this issue to be ruled on by anyone.