Re: .308 @ 1760....
20in barrel 308 win at a mile ? no fucking way, shooting in a 8mph wind at 1500 ft doesnt help either. Maybe if you had a ridiculous LOS angle to target combined high elevation maybe.
your wasting your time even thinking about it. Even if you had a 50 bmg i wouldnt guarentee you'll hit shit at a mile.
you'll never get on target , if you did , you wouldn't stay on target ,
roughly looking at jbm ballisitcs with a 175 gr berger vld moving at 2800fps ( which is faster then what you'll be doing with a 20in barrel) , at 1700y every mile per hour of wind equates to 30-40 inchs , meaning if you were not 100% correct in your wind call you'd get a 40inch group ,( not including your rifle spread , becuase its unlikely your gun shoots 20 shot 1/4 moa groups) assuming you are 90% correct or +/- 1mph across the entire 1760y ( well , probably more like 400-1500y) you'd be looking at an 80in group , as a best case senario ,
we aren't even talking about ES/SD and other factors , you see why your not going to be able to do this ?
thats not to say i dont believe its possible , i seen some unbelievable stuff.
IMO If you are serious about shooting things at a mile you need a much more ballistically superior round. probably 338,300mag ,375/416, 50 cal , 6.5mm , shit like that , stuff with either high bc's , high velocities or ideally both.
but hey , i'd love for you to prove me wrong , i really would.
you should check out JBM ballisitics and get a good understand of exterior ballisitics if you want to shoot that far.