Several things really help me, in making longer shots in the field on big game. One is the use of a Chrongraph (Oehler) and ballistic software (Exbal). Another is the Burris LER handgun scopes (3-12 for me) with the Ballistic Plex Reticle on all of my scopes. Another new twist that has just been made available for Burris scopes is the replacement turret caps by Kenton Industries
http://www.kentonindustries.com/pics/picbytype/This allows you to just simply turn to the distance you are shooting game at and you are dead on (still have to dope the wind). You have to send them your true MV, bullet, BC, Elev. and approx temp. I have one on my 7.82 Patriot XP-100 and it works great in conjuntion with my BP reticle. A rangefinder is a must, to accurately know distances. You do need a scope with a target turret (Or have Burris put one on for you) on at least the elevation for this to work. I think that is a $50.00 to do that.
When shooting at steel this past May, using a Harris Bi-Pod I made single-shot hits from 400 yards all the way to 700 yards on steel using this system. The 700 yard piece of steel wasn't very big either. Last year I shot my buck @ 260 yards with my 6.5-284 and a cow elk @ 385 yards with my Patriot. Yes, I have made further shots, but the point I want to make is that today with what you have available it is easy now to know your vertical drop accurately. The issues are a bullet that performs well at a wide velocity span with a decent BC, accurately doping the wind, solid field rests, state mind (calm) when shooting, understanding the impact of your bullet when shooting uphill or downhill (Angle Cosign Indicator), and practising at the actual distances you will hunt from field positions proving to yourself you can hit what you shoot at.
This may take some of the fun out of just guessing and winging away at a critter, but it is a nessecity for me when shooting at big game at the further distances.