I set my .243 up for long range shots by firstly getting a scope that I could dial, in this case it was a Leupold 6.5-20X50VX3 LR, I then developed a load and practiced a hell of a lot with it at different ranges, Exbal gave me my drop chart, I had to validate the drop but once this was done my rifle was very accurate, although I only shot it out to 500yds.
I have since, had it rebarrelled as a .243ai and changed the scope, it now wears a Nightforce NXS 8-32X56 NP2-DD ret. This scope is absolutely brilliant, repeatable optics are a must for long range shooting in my opinion.
I was out Sunday practising some more and constantly hitting a 5 inch gong out at 500yds, once you know the rifle can do it your confidence will grow, you know then that if you miss at long range you have probably made a bad wind call or misjudged the range. Practice, then practice some more but most of all, have fun practicing. Then you will be ready for that 500yd yote and think "I can do this!"
The above is just my opinion of course and some will disagree, the internet is a placce where everyone is entitled to give their opinion, but opinions do, and always will, vary!
Regards
Mr.Smith