I just got a Primary Arms Advanced Micro Dot with the American Defense cowitness mount.  I'll be putting it on my 22SBR but put it on the MPX for a test run first.  I noticed it gives a lower 1/3 cowitness with the ADM absolute cowitness mount.  I was planning on buying the Larue Tactical Aimpoint w/mount but am not sure now.  Anyone know what the LT 660HK would be on the MPX?  I want it lower closer to cowitness and not lower 1/3.  Open to other options as well.  

Thanks!