Frankly, it can be a great weapon for some experts. Not a novice. Learn what you are doing, and a.308 will do that to 900 meters. You might also look at some of the calibers being built just for long range- think the world record for best long range group is a 6mm round.
If you get a .308, you will shoot it a lot more, and enjoy it more.
Good luck, let us know what you come up with, and go shoot something.