Higg,
I have never believed that you can be "over gunned" but my next deer gun is going to be a .243. I hunted for several years with a 6MM Rem. I got rid of it, and regret it! After hunting with my .308 and 7MM RM, I have not seen any real advantage of these calibers for most deer hunting situations!
When I say "the .243/6MM makes a GREAT MINIMUM deer cartridge", I mean EXACTLY that! A GREAT minimum! Not just a "barely scrape by", but a fully capable cartridge for most any deer hunting needs!