AR15-A3 sighting-in issue

[*chris*]

I have an A3 style 16" upper with a standard gas block and sight and a flat top upper. I am sighting in the rifle using the RIBZ method and while my elevation is perfect, the windage is cranked almost all the way to the left and the POI is still slightly to the right of the bull at 50 yards. I shoot left handed if that matters. I am pretty sure something is wrong with the rifle, but I am not sure how to check/measure. Since this rifle was built during the height of the insanity, I guess the front sight and barrel could be canted. I bought a no name detachable carry handle from the Marlboro show, but it mounts solidly and looks good.

How do I start measuring to figure out the problem? I see that the barrel is indexed to the receiver, so is it possible that the front sight was drilled incorrectly? Is shimming the carry handle with a brass shim a good approach?

Thanks

Chris

 

[je25ff]

Are you sure you aren't tugging on the trigger?

 

[*chris*]

Are you sure you aren't tugging on the trigger?

Positive, just using a front rest I was producing 3 shot quarter sized groups with iron sights at 50 yards. I was also shooting my PC9 which is spot on. My shooting buddy had the same problem with the gun.

Forgot to mention that I had a red dot mounted and dialed-in with no problems at all. I just prefer the iron sights.

Chris