Truth be told, it doesn't matter to me which one he takes, except for the fact that he live just outside Philadelphia, and his Mom will have to drive him to a range. Ammo is almost non-exhistent. His Dad is about to deploy to the sand pit.
For now, the 22 is the best option. He can take ammo home with him from here, and his Mom can help him with learning to shoot.
Later he can have what he wants.