Originally Posted by
darkker
Run the energy numbers for your "600 yard" question.
The Creed is a beautiful standard short-action cartridge. The Grendel is designed specifically around the short AR-15 action length.
So.... What do you want? If you want to take advantage of the full short action length of a rifle, thus a bit more speed with light bullets, and significantly more with the heavies; take the Creed.
With the 120 class bullets, there really isn't much difference if you are popping targets @ 500.