Problem with rear sight on a fixed carry handle AR-15

[Iron Sights]

A friend has an older fixed carry handle Colt AR-15. The rear sight needs to be adjusted all the way to the right just to bring it to the right edge of the 5 1/2 inch target at one hundred yards. The front sight looks good. Looking close, it looks like the rear sight is not aligned with the carry handle, it is a little to the left of center. Is there an easy way to correct this or is it a major job?

It does not appear that the rifle has been damaged in any way other than the rear sight not aligning with the carry handle, not much but just a very little. The carry handle does not seem to detach from the upper. Rear sight is tight. We have tried several different brands of ammunition and the barrel is marked NATO 5.56 1/7.

Any help would be appreciated.
Thank you

[LMTguy]

If all looks good at the rear sight try looking at the front sight. Is everything tight? My thought would be it would be much easier to damage the front sight and knock it off center.

On a side note is your friend a good shot to begin with? Trigger pull?

[SgtSteve]

Hey Iron Sights how you doin'? Good except for this little problem right?
I have the same Colt AR, large pin, which means "old". In fact like a 1980s type old just after they stopped making the triangular shaped front grip.
The one piece of info you got...the front sight...making sure that blade isn't bent. In fact get a sharpe point object and push down on the retaining pin that stops the
front sight front rotating. Rotate the front blade one or two notches up or down, no big difference.
If that's done and good now look at the piece of metal/steel that houses the rear sight. Take it between your thumb and forefinger (holding it by it's "ears") and see if you can wobble it. Try twisting it like you were opening a bottle cap. Sometimes this base is either loose or there's a space between the ears and the contact surface that allows it to rotate slightly in place. This will throw off the opening/the sight hole and place the entire rear sight on a slight angle. Still not good?
OK, using the rear sight elevation know extend the elevation know the whole way up or down...don't worry a bout elevation...the concern here is that the thumb screw may bekicking off the base of the rear sight. Last but not least, check the screw that tightens and moves the rear sight left to right, sometimes it loosens.
Last but not least check the flash suppressor it could be loose! Hope if works and if nothing else then throw the whole rear sight in the crap can and replace it with a Mag Pull!
Sgt Steve

[Iron Sights]

Thanks Steve for the advice.

Whiled the front blade does not look like it is bent I will try rotating it. There is no movement where the rear sight is located and the sight is tight. The elevation adjustment is something I have to try as it is something I never thought of. The adjustment screw is tight as it pulled the sight all the way to the right and can't go any further. The flash suppressor seems to be permanently attached.

How do you remove the rear sight?

In addition, several people have shot the gun and it shoots to the right for everyone.

[USMC3531]

may want to remove the flash hider and have the barrel recrowned, its also possible the barrel is bent or the whole front sight assembly is canted to one side.

[Hawk]

You can try re-indexing the barrel in the upper to move the FSB to compensate. Only a very little rotation in the barrel will make a big difference in windage. If there is no room to rotate the barrel in the uppers indexing slot (see below), you can widen one side of the slot (the direction you need to rotate the barrel) with a file and then clean up the threads. Just make sure that when you torque down the barrel nut you don't move the barrel.

BCMbarrel.jpg

[39flathead]

Hey Iron Sights how you doin'? Good except for this little problem right?
I have the same Colt AR, large pin, which means "old". In fact like a 1980s type old just after they stopped making the triangular shaped front grip.
The one piece of info you got...the front sight...making sure that blade isn't bent. In fact get a sharpe point object and push down on the retaining pin that stops the
front sight front rotating. Rotate the front blade one or two notches up or down, no big difference.
If that's done and good now look at the piece of metal/steel that houses the rear sight. Take it between your thumb and forefinger (holding it by it's "ears") and see if you can wobble it. Try twisting it like you were opening a bottle cap. Sometimes this base is either loose or there's a space between the ears and the contact surface that allows it to rotate slightly in place. This will throw off the opening/the sight hole and place the entire rear sight on a slight angle. Still not good?
OK, using the rear sight elevation know extend the elevation know the whole way up or down...don't worry a bout elevation...the concern here is that the thumb screw may bekicking off the base of the rear sight. Last but not least, check the screw that tightens and moves the rear sight left to right, sometimes it loosens.
Last but not least check the flash suppressor it could be loose! Hope if works and if nothing else then throw the whole rear sight in the crap can and replace it with a Mag Pull!
Sgt Steve

Gonna be difficult to mount a Magpul rear sight on a fixed carry handle AR.
Mabye he could try using gorilla tape or something to hold it on...

[39flathead]

OP, a picture would be great.

[bigandy1966]

You can try re-indexing the barrel in the upper to move the FSB to compensate.Just make sure that when you torque down the barrel nut you don't move the barrel.

probably slide a small piece of shim stock ob the side you filed down to hold it in the new indexed position.
Or buy a flat top upper, replace the front sight with a picatiny gas block mount the optic, and call it a day

Thanks Steve for the advice.
The flash suppressor seems to be permanently attached. .

well if its welded then I guess your friend will have to do the re indexing thing because I'm pretty sure the tower front sights do not fit over the flash hider.

[Iron Sights]

You can try re-indexing the barrel in the upper to move the FSB to compensate. Only a very little rotation in the barrel will make a big difference in windage. If there is no room to rotate the barrel in the uppers indexing slot (see below), you can widen one side of the slot (the direction you need to rotate the barrel) with a file and then clean up the threads. Just make sure that when you torque down the barrel nut you don't move the barrel.

BCMbarrel.jpg

That sounds like something beyond our abilities. Thank for the advice. I guess he has to take it to a professional.