I was sighting in my AR yesterday at 50m and noticed that my POI was about 12in. from my POA with my rear sight aperture perfectly centered in the center of my rear sight. So I start adjusting it to the left until it's still 2-3 inches from POA. Is there anything I can do to fix it before sending it in for repairs. By the way the AR is a bushmaster.

FYI zero at 50 yards not meters.

Anyway... 12 Inches!! Holy $H!T I didn't think there was that much adjustment available.  I'd send it back and have them re-torqe the barrel.

Give them a call and they will pay for the shipping.

For vertical stringing you need to adjust the FRONT sight post, not the rear.  You want to set the rear sight so it's at the 8/3 mark, and can go DOWN 2 clicks.  Leave that alone and adjust the front sight post for vertical zeroing.

If it is to the side, yeah, the barrel might be out of index, or the receiver could be warped.  It should be pretty much right on with the rear sight centered.  

in one of my AR15 books on customizing, accurizing etc., it shows how to fix this problem, but cautions to, "...NEVER let a customer see you do this", but his method is to place the left or right side of the muzzle on the work bench, support the action over your shoulder &, "...give the front sight a good "whap" with a firm rubber mallet..."

that worked for me too.....

just thot i'd add that in if you send it back, thats all their armorer will do.....

You do realize, in this case you could've NOT said the manufacture and we would have still known who you were talking about.

It's really to bad, I've had nothing but problems with my bushmaster.