I am GUESSING it is not the bullet. I have not shot the 162 (A-MAX) at 1800 yards, but I have used the 6.5 140 grain (A-MAX) to that distance, and I have a friend who has done the same with the 30 cal 168 (A-MAX).
My guess is that it is your load, if you are getting 12" of vertical at 1K.
In...