Greenhorn and Wapiti ,
Possible to find ONE POWER SETTING for all ranges . May have to alter sight in distance as per Wapiti's suggestion but not necessarily .
eg. When sighted in at 200 yds I found that approx 18 power gave near perfect results for my .243 Ackley shooting 70gn Nosler BT at 3550 FPS . This is not one of Leupold's recommended power settings on the 6.5 - 20 VX 111 .
Just changed to the 55gn Nosler BT at 4030 FPS and found that the same power setting will be good if I sight in at 250 yds . Trajectory of the 55gn is virtually identical to the 70gn albeit at 50 yds longer ranges . 55gn drops about the same at 350 , 450 and 550 yds as the 70gn at 300 , 400 and 500 .
Need a chronograph , your bullet's B.C. and a ballistics program to work this out easily . Good free web - based ballistics program at http://www.beartoothbullets.com/resc...stics/DATA.htm