I would suggest starting out with a Ruger 10/22, since 22 LR ammo is inexpensive. And the rifle is easy to sell if he ends up not being interested. It can be used for Steel Challenge as well as CMP Sportster. Sadly, the youth shooting sports are not very active in public schools in the metro area. But the 4H groups outside of the metro are usually pretty active with at least shotgun sports.