I was zeroing a 16" BCM that I recently swapped the 13" KMR for a 15", following instructions to the letter.

I got it zeroed on the bench, riding sandbags. Shot a few groups and was satisfied it was printing where I wanted so I left the bench and went to the bipod. .5 mil shift down from on the bench. Went back to the sandbags, POA=POI. Back to the bipod, .5 mil low.

WTH??