I feel it's important to note that at those distances it's the SHOOTER.... FEW (if any) here are as good of shots as 3rdRCN and E.Shell (I don't ever venture into the long range section so I could be wrong).
Thanks for the compliment X-Factor! There are quite a few guys on here that I shoot with that I think are better shots than I am. That being said, I agree that alot has to do with the shooters ability and if the gun is capable of those distances. If a gun will shoot 1 MOA then you have a 10" at 1K gun, this will likely not be very competitive as it leaves no room for error. If a gun shoots 1/2 MOA then it is a 5" at 1K gun, this will be much more accurate at 1K and can be a competitive gun for shooting long distance. These numbers are assuming the caliber has the ability to stay stable out to 1K as well.
If you have the desire to shoot long range I would really suggest getting some good coaching. There are many factors that need work when going long such as body alignment, trigger discipline and rifle management just to name a few. I used to think that breathing was an important aspect but took some lessons from a very well respected long range shooter and discovered that breathing was over rated as far as what you should be thinking when behind the gun. Once you get those items down then you start working on the wind, which is a huge influence on almost every caliber when you go to 1K.
E. Shell has been a student of CVT for quite some time and he can vouch for the expertise of this particular gentleman's school. It is worth every dollar if your serious about shooting a "long" gun.