I know its normal but it kills me to have to see it so tilted to the left that I can see the ball bearing.I have 2 FK and 1 BK marked upper where the sights are perfectly straight even with normal side to side movement but an A2 upper I have marked A with + upside down L..thats how it looks on the upper I have was agravating to see the tilt so this is what I did.

I dissasembled the rear sight and on the right or ejection port side of the carry handle right behind the forge mark I use a 1mm thick line of JB weld.I filed it down until the sight fit comfortable and now its perfectly straight even with side to side play.After I sanded it to the thickness I needed a quick spray of flat black duplicolor 1200 degree black and a 1 hour baking on 300 degrees and you cant even tell.

So its essentially a one sided JB weld shim.

It never bothered me much, but I know some can't stand it...

For some reason it just looked to canted.I just dont get how some do and some dont.Do you think its a machining dimesional issue?My FK and BK uppers are more than 10 years old and the rear sights are straight as can be even with play.

How’s that saying go…….”Don’t fix something that ain’t broke!”  

I hear ya but I still dont understand why some do and dont and can it effect sight alignment?the thing was also when I was usuing this upper I carried it in the ready posistion and it kept snagging on my gear,LBE straps and such when resting against my chest as thats the side that formaly turned out.Im starting to think I should just switch to flat tops with BUIS rear sights and be done with the canted eye sore gear snag altogether.

I really don't think you can call it an issue...  Some do it and others don't.  It has no affect on accuracy either way, at least none that you can speak of...

The only real issue I had was snagging,,other than that your right..eye sores aerent an issue.