I have become so weary of the 'Caliber Shaming', that I just tune those people out, anymore. I can't remember the # of 'bigger is better' discussions I've read / heard when it comes to ethical or effective hunting. As previously suggested, just tell them to take your money and do the work, or you will find someone else who will.
Being a gunsmith doesn't qualify me as an expert on hunting any more than being a hunter qualifies me as an expert on gunsmithing. SDGuy - with due respect to your gunsmith(s), allow me to offer the following: