No dog in this fight..and there was no mention of velocity for either bullet, but a simple check with Hornady Ballistic Cal. indicates a 7mm 162 gn. BTHP at 3100fps needs 33 MOA to reach 1200 yrds. The 180 Berger at 2900 fps, needs 34.2 Bump the Berger up 100FPS, and things begin to change. But that`s about the "foot" he saw.
The wind drift will be more with the 162 grain
