I believe the 357 will do the job. How about you do the ol switcheroo with a 44 mag meaning get him started shooting mellow 44 mag reloads and when you go hunting slip in a hot 44 mag he wont even know the difference he will be to excited to care. Thats what my dad did when i killed my first turkey. I practice with low brass 20 gauge but he slipped in a 3 in magnum and I killed the turkey and didnt even know about it until afterwards.