I was sold the Official Low Profile Mount... and a cheap optic for it... later returned the optic, at which point i noticed the skew.
After a lot of searching, I determined that "This is just how it is"...
Examination showed that the coating on the front-most those two squared metal tabs was worn a bit from contact with the slot in the mount - mmm.
I got out a VERY fine metal file, and whisked the coating off, and squared the tab. Probably shaved all of 1/2 mm.
The mount is now perfectly centered and level. Slapped a holosight on their (hey, look at the nickname ;>), and a bore sighting test was like wow, at 30 yds, almost on the money with no adjustments. Sweet.
Now, I think I would LOVE to have one of those wee extenders, that provide a direct view with the iron sights if one wants, for fun/practice/backup. They look to be about $20 on ebay, but I don't know the quality of any given model (CNCed metal, plastic, junk), advice?
Got a kit with a new buffer, and screws, and such coming. Can't wait.
Also can't wait to find a decent 3-point sling (also for fun, and ease of carry). In particular, these guys look like they have something useful: http://www.urbanertslings.com/3point.html and one could use it on other items as well.
Holo