Dave, I think you'll find the .243 will be the perfect round for your boy. He'll have a rifle to grow with him. I bought one many years ago for my wife and before too long, I adopted it for myself and have taken more game with it than I care to admit to. As well as the past pad, I'd recommend seeing if your reloading buddies can load you up some mild 75-85 grain loads to start with. let him get used to the mild recoil then bump him up to the 100 grainers, if you want. You mentioned the noise. Think you'll find the .243 cracks pretty good too. Get him some ear plugs to wear WITH muffs to quiet things down good. Midway also has some electronic muffs on sale now for under $50 that really work great. Good luck and keep us posted!