Is it me, or has anybody else noticed that the EoTech sight, when mounted on to the flattop receiver, is tilted to the left.  It just does not seem to sit flat on the right side.  This caused the shooter to put in a lot of windage adjustment.  I tried it on several flattops and it sits high on the right side on all of them.

Got a 551 and 552 both sit completely flat on the receivers.  Both are on RRA uppers.  Remove your and reinstall it sounds like it didn't go all the way down on the rail.  Maybe you bent Eotech or its integrated mount by overtightening it?

I thought I had the same problem with a bushy upper.  Turns out that the front sight assy. was canted and it created the impression that the sight was canted.  I straightened out the can't and the site is perfectly centered.

Hateca,

I've got the exact same problem with my EOTech 551.  I started a thread to discuss the issue and work the problem.  

My Co-Witnessing An EOTech Thread

I'm glad to know it's not just me.  Mine was not caused by a front sight cant.  The EOTech sits tilted to the left as evidenced by reading a bubble level.  The reciver was held in a vice in a level position.  The front and rear sights are both showing as level.  The EOTech is canted forward and to the left.

I used the windage and elevation adjustments to bring the dot to the top of the front post.  I'll fine tune it at the range the next time I get up there.

Ok I think I figured it out.  I took out my three flattops and put the EO on all three.  The Bushmaster was the worst.  The Model 1 was better, and the RRA was the best, it was near perfect.  (bubble level was used)

There seems to be a slight difference in the machining of the flattop rail +/-.  The upper and lower angle cuts appears to vary a few degrees from receiver to receiver.

I don’t know if this is an acceptable tolerance in the receiver, or if it was just bad machining.  Anyways I did some swapping of sights receivers and barrels to get the RR receiver where I wanted it.

I think the way the EO mounts, it grabs these angles and it can cause a tilt.  If you look at the bottom of the sight, it is flat, but if you look at the left and right V-rails the right rail, that is used to tighten against the flattop, is higher.