I understand your reasoning about using bigger cartridges on extremely long range due to better wind bucking ability. The thing is,most of the best 6mm/.25 cartridges for long range are wildcats. In factory form,it's hard to beat 25/06,6.5mmx284,and the various overbore 7mm and .30 magnums. Just hor far are you willing to go for ultra long range rig? Does it HAVE to be a factory cartridge or can it be a wildcat or something along the line of allen magnums or lazzeroni?