Managed recoil ammo is the way to go. Son started shooting a 308 at age 8 with this ammo and daughter started shooting 30-06 with this ammo at age 10. Cuts the recoil in half. A huge benefit is that my kids have been hunting with the same guns their entire life. They are very comfortable and proficient with these guns and moved up to regular ammo loads after 3-4 years of shooting the managed recoil loads. As long as they kept their shots to within 200 yards, it's great stuff. And buy your kid the best ear protection you can find. Minimal noise and half the recoil will be a great way for your son to start.