The range that I normally go to is about a ten minute drive from larue... So, after i got the mount, I just went to the range, mounted the scope in their classroom, then zeroed it.
the 10" shift I was surprised at, though. I knew there would be some shift, particularly if I am I mounting and then remounting an optic from the mount itself (vs removing the mount/optic as a unit), but it was about 1/8" when all is said and done.
10" almost exactly. Dang.