I purchased a complete stag A3 upper with an arms#40 from a local dealer when they transferred me my lower. Just now I've been able to get to the range to sight her in.
The only mod I've done is add a troy mrf-c rail.

At the range, I had to crank the arms#40 to the right. It got to the point where it was nearly out of adjustment and I was still hitting to the left a few inches at 25yd!

So I say ok the barrel is probably canted and can remove some material on the notch in the upper.

I slap my Eotech on it and try sighting in with that. Guess what...had to start cranking that to the right too. Well this Eotech was on my AR-10 and another AR-15 and didn't have to adjust L-R much at all.

Am I dealing with a bent barrel here???

sounds like a bent barrel to me but I am no expert


Stag does have great customer service.  Don't hesitate to call them.

http://www.ar15.com/forums/topic.html?b=3&f=66&t=276986

Any answer yet? Thanks.