The reason I thought a 30-06 would be good is because the OP was also making considerations about his 12 year old son. Nobody else made any suggestions from that POV.
People can work their youngsters up to sensible amounts of recoil, having first learned good fundamentals with small bores and smaller shotguns, 30-30's and the like. The 30-06 is a cartridge that exists with a range of loads and therefore recoil. I'm no expert, but my son went this route and when he was 15, I covered his 100yd groups with a dime. 200yds, he liked blowing up golf balls. At that point I realized there's no substitute for youth!
Of course
he believes it was all talent.
Good luck, Diggs.