Eh, I know this goes against the logic of many folks including those in this thread but I purposely ordered him a rifle with no sights. He has shot his BB gun with irons and has shot other rifles with irons some, he does pretty good with them but they don't interest him nearly as much as a scoped rifle. I opted to get him a rifle with a scope to keep him interested/excited in it long enough to learn the basics of trigger control, body position, safety, etc. etc. I have a 10/22 with irons that he can try later on if we get to that point.
I know it sounds ass backwards but my first rifle had open sights, I was dead on with it as most kids tend to be but I quickly got bored and wanted a scope. Its been that way ever since. I rarely shoot irons but when I do I know how to make them work partially because the rest of my fundamentals are pretty solid. In fact, the last two times I shot irons was in classic battle rifle matches, with a K31, against plenty of scoped and/or semi auto rifles, and I have a 2nd and 1st place finish out of them. The 2nd place finish was with a borrowed rifle which I had never shot or knew of until right before the match when I put two rounds through it to check out the action. I loved it so much I bought my own, put 5 rounds through it to verify it was sighted in before a match, then won the match.