I would like to build a rifle for 600 yard shots on deer/coyote. I am new to long range so i am curious as to which calibers will work better than others. This is going to have to be a new rifle as i only own a Ruger 22-250 cabale of 5 shot 1 MOA groups at 100 yards but cant use on deer in washington, and i also have a 30/06. Im thinking of a 7mm mag, stw, or ultra mag. Let me know what you think of these calibers or what would be better, not currently reloading just using factory ammo. Any insight to a newcomer would be greatly appreciated