Its really going to depend on how well you're son can handle the recoil and what all he's planning on hunting in the next couple years. If he can handle the 410 and isn't scared of it I would say you could do one ofthree things.

1. Get the 410, pattern it, and turn em loose with it. Absolutely nothing wrong with the 410 for small game and upland game. I've killed alot of animals with it.

2. Look for a 28 ga. It doesn't kick that much harder than the 410 and it'll give ya alittle bigger pattern than 410 and is one heck of good gauge for small and upland game. Then if he's lookin to deer hunt you just look into a muzzle loader.

3. If you reload your own stuff then my suggestion is to do what my dad did with me. Get him the 20ga. and cut down the load to about half. It kicks about the same as the 410 and he shouldn't have the much of a problem dealing with. Then he'll have a gun that will last him quite a while as an all around gun.

Either way I'd look at a single shot to teach marksmanship.