Two things. First, 2700 in a 24" .308 with a 180 is very optimistic. Nosler only gets slightly over 2600 with their data, and 2730 for the Creedmor and 140s. So you've got that.
And then wind drift. At 1000 yards, you have to hit the animal before "energy" even comes into play.
I'll take the .600 BC over the .509 for hitting at 1000.
