It's not a question of age but one of maturity. After all, there's grown adults that cannot and should have possess and use firearms. I'd do what I did with my son if I was to do it again. Start him with a bb gun and teach him the basics, the fundamentals. It's a inexpensive investment and inexpensive to shoot even in the backyard. Then progress at HIS pace to the 22lr. keep it interesting for him with different target types. Eggs, lolipops and fruit make good responsive targets for kids. Another important aspect is to not pressure him and push him into it. Push too much and he'll really not want to do it. It's gotta be about what HE wants not what YOU want. After all is it for him or you?