I have an Armalite M-15A4 .  It used to have a BUIS mounted, which I traded away.  I recently bought a new Leupold VX-1 scope, and mounted it into the scope mount that came with the rifle.  

I can not get the scope to sight in using the existing Armalite one piece mount that came with the rifle.  The horizontal cross hair is way too high, even when adjusted all the way down.  It remains high when the scope is rotated 180 in the mount, indicating to me the barrel and rings are not aligned.

Do you have any recommendations to better align the scope?  I don’t believe the scope is out of whack--I believe it might be the mount.

Are there shims that can go on the rings raising the back of the scope?  Is there anything else anyone can recommend?  I am looking for someting I can do myself, not return to Armalite for replacement.