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11/5/2007 3:38:07 PM EDT
I just finished sighting in my new 16" bushmaster. After dropping the front post 2 notches and cranking the rear apperature ALL the way over to the left. I added an Aimpoint red dot on a arms mount. At 50 yds. it groups nicely. BUT, my question is, WHY is my rear back up iron sight so far off? When I look down the rifle from the rear, everything seems rotated clockwise. Its a A4 modular carbine. The iron sights are both flip up. Is this common for Bushmaster? Any info you guys can give will be helpfull.
Thanks!
11/5/2007 3:42:27 PM EDT
[#1]
FSB canted, or barrel indexing off.
11/5/2007 3:46:49 PM EDT
[#2]

Quoted:
FSB canted, or barrel indexing off.



Is it amazing how many Bushmasters ship this way, or what?


One would think this is an easy fix at the manufacturing level.
11/5/2007 3:51:49 PM EDT
[#3]

Quoted:

Quoted:
FSB canted, or barrel indexing off.



Is it amazing how many Bushmasters ship this way, or what?


One would think this is an easy fix at the manufacturing level.



Seems like just about any AR lately. I don't know how many threads I've answered recently for this same problem.
11/5/2007 4:16:41 PM EDT
[#4]

Quoted:

Quoted:
FSB canted, or barrel indexing off.



Is it amazing how many Bushmasters ship this way, or what?


One would think this is an easy fix at the manufacturing level.


My bushmaster that is over 10 years old had this same problem.  I love the gun but you would think they would get this assembly step correct after how many 1000's of guns they have produced.
11/5/2007 5:06:07 PM EDT
[#5]
My Colt 6921 upper was canted, after I took my jewlers file and made some adjustments it works great, know that I ran a railed block I'm kinda pissed I filed part of my reciever off. So its not just Bushmaster.
11/5/2007 5:52:08 PM EDT
[#6]
Slightly loosen the front sight clamping screws and see if you have  some movement left and right. It may be only a small amount. Center your rear sight and attempt to zero windage with the front sight. It worked on mine.
11/5/2007 8:04:14 PM EDT
[#7]

Quoted:

Quoted:
FSB canted, or barrel indexing off.



Is it amazing how many Bushmasters ship this way, or what?


One would think this is an easy fix at the manufacturing level.


+1

11/6/2007 4:27:59 PM EDT
[#8]
so, can I fix it myself (other than fudging the front sight), or being a brand new firearm, will Bushmaster fix it or replace it?hinking.gif
11/6/2007 4:55:57 PM EDT
[#9]
Let them fix it.This seems to be an everyday problem with them.You would think with them knowing this they would pay more attention to deatil.Not for nothing but if they testfired the rifle with like 10 shots from the factory they would see themselves if a rifle was off before it shipped.They should be taking care of the prolem before it leaves the factory.Factory doesnt seem to be the way to go anymore...hell you could have one of the many vendors here make you a rifle for probably the smae with quality parts that will have none of these issues out of the box.
11/6/2007 5:56:42 PM EDT
[#10]

Quoted:

Quoted:
FSB canted, or barrel indexing off.



Is it amazing how many Bushmasters ship this way, or what?


One would think this is an easy fix at the manufacturing level.


+2 on that.

Mine is canted a little (11 clicks to the left) but it shoots great so I decided to leave it alone.
11/6/2007 6:37:22 PM EDT
[#11]
Bushmaster would really save themselves some time and money, if they would just include an RMA number with every rifle.
11/6/2007 8:21:58 PM EDT
[#12]
My buddy sent his upper back and they laser bore sighted the barrel and sent the target back with it that they test fired it on..do that in the first place and no mistakes leave the factory.
11/6/2007 8:24:42 PM EDT
[#13]

Quoted:
My buddy sent his upper back and they laser bore sighted the barrel and sent the target back with it that they test fired it on..do that in the first place and no mistakes leave the factory.


Jarrod, the rep in the BM forum, claimed a few years ago they had started doing that to rectify the issue.  Guess that wasn't the case.
11/6/2007 8:32:34 PM EDT
[#14]
My first Bushmaster came like that.  I sent it back and they returned it fixed.  My next three Bushmasters were fine.  

My LWRC initially came like that, but they fixed it also.  

Is it really a canted front sight base?  I thought I remembered Bushmaster saying the barrel was over torqued.  But it WAS a long time ago, and I could be mistaken...
11/6/2007 8:42:28 PM EDT
[#15]
For the FSB to be canted, doesnt the pin on the barrel extension have to shear?
11/6/2007 8:50:15 PM EDT
[#16]

Quoted:
For the FSB to be canted, doesnt the pin on the barrel extension have to shear?


Not necessarily.  I worked with a barrel recently (not a BM) and the index pin and FSB were not aligned.  Either the index pin was off or the FSB was.  Overtorquing and damaging the pin or receiver is a common reason for the problem, though.
11/6/2007 9:34:34 PM EDT
[#17]
yea isnt the pin a softer steel that can be deformed if not careful.Ive seen them as replacement parts.Also isi t possible to have an extension thats off?
11/7/2007 2:58:00 PM EDT
[#18]
Thanks guys, I paid good hard earned money for my Bushmaster. I think I will contact BM and see what they say..I'll let you guys know.
Thanks!
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