my wife uses a 300win mag I love the 6mm but when useing it to hunt elk I was forced to pass up some shots I wouldnt even have thought about passing on w/ a 7mag or up. I to once thought the 270 was an elk gun, but it to is marginal for use on elk, it'll work as will the 243, but you HAVE to be willing to pass on shots even if you see that bull of a lifetime, I wouldnt want to pass on a 350yd shot at a 350+BC bull because I was carrying my 6mm instead of my 300