I agree about the flattest shooting round. My antelope rifle is a 264 win mag. I wouldn't go with a larger case personally, the 264 will have better barrel life than most people give it credit for with heavy bullets and frequent cleaning with a good copper solvent. It is one of the few calibers that Graybull precision lists on their webpage which is a good advertisement in my book. The 6.5WSM discussed earlier would also be a sweet choice.