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5/1/2012 8:00:05 AM EDT
Hey gang,

I installed a new mid-length free float rail yesterday.  I replaced my full length as I wanted a little less(and I'm a tinkerer...).

I am using Magpul BUIS in addition to my red dot.

Here's some background––when I installed my front sight on the first rifle length rail, the rear sight had to be completely over to the right for it to be sighted in correctly.  I eventually compensated for this by turning the quad rail clockwise(tightening the barrel nut slightly) to get it more aligned.  You could barely tell the rail wasn't matched to the rail on the body of the gun.

Here's my dilemma, yesterday I installed the new rail, this kind connects to the upper body rail(seamless).  I used my A2 carry handle to really clamp it and align, however, I ran into the same problem, my rear sight has to be all the way to the right before it will sight in correctly.

Is there a chance I have a bad front sight, slightly out of spec and the front sight post is either angled or the way it mounts is off-center?

Any input it appreciated.
5/1/2012 8:47:43 AM EDT
[#1]
i don't quite understand your problem have you shot it? if just aligning the peep hole and post are different with rifle and mid length rails.
5/1/2012 9:00:24 AM EDT
[#2]
Yes, we shot it today, laser bored it yesterday.

It's in alignment at this point, but just not sure why the front sight seems to be sitting so far right that the rear sight can't adjust windage enough to compensate.

Rear sight––all the way to the right.

Point of impact to the left of front sight.  Like front sight is too far right to compensate.  If I twisted the rail to "lean" more to the left, it would help, but then the rail is out of alignment with the body.

But because this is the second rail I've had this problem with, I'm leaning more towards there being something wrong with the front sight.  I'm going to try another front from someone tomorrow(if they remember to bring it).
5/1/2012 10:24:16 AM EDT
[#3]
Check and see if the bore is in line with upper.
Check and see if the barrel is straight.
If the answers are no and yes you have an upper problem or a barrel installation problem.
Keep in mind it does not take much to be considerably off at 100 yards.
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