I was figuring you were just letting your son gain some confidence and experience with the rifle before switching to the shortgun.
PS, congratulations to your son!!!
TC, that's part of the reason. He has got several kills under his belt, considering his age, using his rifle. I mainly wanted to let him get some handgun hunting experience on small game with a 22lr. This allows field position practice and respect for the difficulty of handgun hunting. I think he will be ready by next season.