OK, here we go again...  A couple weeks back I posed an argument for the forum regarding where one should place an item that is to be mounted on a rail (i.e. push it as far forward as possible then lock down or pull back as far as possible then lock down).  
www.ar15.com/forums/topic.html?b=3&f=118&t=273301
The general consensus was to push it as far forward as possible then lock it down.  I now ask this, when mounting an Aimpoint inside the ring do you fellows push the optic as far forward as possible so that the ring is flush with the flat part of the tube or do you pull the optic back so that the ring rides on the edge of the tapered part of the tube?  Here is a picture of my set-up for clarification:

Mine is pretty well centered.  But of course that doesn't make it the right way, just my way.

BTW nice LaRue canti mount.

I also have mine close to center.

If you would like yours mounted a little forward than the middle it's up to you.

There is an inside radius on the Aimpoint that your mount could be hitting, I would recommend that you move your sight back a little like about 0.05" to 0.10".

If the radius of the Aimpoint is not hitting the back edge of your rings that would be fine then.

Wow!!!  Who knew that fraction of an inch could matter so much...  I just took out the tools and moved the M2 up about 1/16th - 1/8th inch off of the flat part.  You were exactly right about the radius from the milling (or welding?).  I was able to get the ring quite a few revolutions tighter than before.

Could the ring hitting that radius on the Aimpoint cause the optic to shift a bit, i.e. not be as secure so a simple bump could knock your POI of a bit??

I'm not sure and never gave it a second thought until Alpha-Romero 3 mentioned it...  He was absolutely right, however because I was able to thighten the ring down several more turns, resulting in a noticably smaller gap between halves of the ring.  It stands to reason that if the majority of the pressure from the ring was being placed on the radius, with a slight gap throughout the rest of the tube, that a "bump" could cause a shift.