Teach Deer, it sounds like you have done an excellent job of getting your son started down the right path to gun safety and management. Shooting paper targets is one thing, but put something in front of a person that actually has a reaction when shot and it just seems to be much easier to focus. I know it works that way for my son, and even myself. There was an article in Rifle magazine, and another in Handloader on reduced recoil loads in larger calibers being better out to given distances than full power loads on smaller calibers. It makes sense, being the larger caliber has more frontal area and therefor more shock value.