iron sight alignment

[TSully]

Thanks for all your input guys, I have sent another e-mail to BCM letting them know the rear sight is 29 clicks left of mechanical zero to line up. I can see no issue with the Magpul by just looking at it. However as one of you mentioned, it is plastic. For that matter, I can see no issue with the FSB by just looking at it either. I will upgrade this as soon as something better can be ordered and recieved. I am determined to put together a quality weapon as I am in pretty deep already. The red dot I used is just a cheap bsa I use on a shotgun, I just wanted to put something on there to see what it would look like should the need to use irons arrise.

[Caduceus]

tag for answer. I have a similar problem: LMT upper (sighted fine on BUIS), but my trigicon 1.5x reticle is approx 15 degrees up and right of the FSB. Seems to be OK, but that blurry FSB being off-center so much really concerns me.

[TSully]

Exactly, makes it difficult to witness, for lack of a better term. I feel I would be better off without the FSB all together.

[Mr Elbowseed]

You should be able to get a carry handle cheap on Ebay or the EE then you can narrow down if it's the mbus or the upper

[SteveL]

I have Magpul BUS on my rifle as well and the rear is almost all the way to the left. I ended up having to have the upper receiver itself replaced and I had hoped that the sights would zero more toward the middle with the new one, but they didn't change much at all. I finally decided not to worry about it. I got the rifle zeroed with the BUS and that was the primary concern.

On a side note, it seems every time I see this issue brought up about the Magpul BUS the rear sight needs to be moved far to the left. Never to the right.

[jwperry]

I finally decided not to worry about it. I got the rifle zeroed with the BUS and that was the primary concern.

On a side note, it seems every time I see this issue brought up about the Magpul BUS the rear sight needs to be moved far to the left. Never to the right.

This isn't only related to MBUS, this seems to be a decently common question.

If you're able to zero the gun, even if you're near the edge of adjustment, you're OK as long as everything in your upper has been put together correctly (barrel nut torqued right, sights installed tight and good lockup on the BCG/barrel extension).

[SteveL]

If you're able to zero the gun, even if you're near the edge of adjustment, you're OK as long as everything in your upper has been put together correctly (barrel nut torqued right, sights installed tight and good lockup on the BCG/barrel extension).

I got it zeroed without any problems, and it still has some remaining adjustment to the left so I'm good to go. The upper as it was originally was factory assembled from DD. As it is now, it was assembled by a local guy who is top notch so I'm not worried about assembly. It bothers my OCD more than anything but I'll just have to live with that.

[markm]

On a side note, it seems every time I see this issue brought up about the Magpul BUS the rear sight needs to be moved far to the left. Never to the right.

Same with that TROY crap. There was a while were the same thing was popping up on their rear flipper too.

[GeorgiaBoy]

I have a BCM 20" A4 upper that with a DD A1.5, Matech, and Carry Handle needs to have the rear sight moved 13-15 clicks to the left.

This isn't a problem with any other carbine/rifle I zero.

I have a feeling that BCM IS occasionally putting out uppers with SLIGHTLY canted FSB's. I've read quite a few accounts of BCM uppers needing substantial left adjustment and it keeps being blown off as "a shooter problem" or a "rear sight problem".

[markm]

I have a feeling that BCM IS occasionally putting out uppers with SLIGHTLY canted FSB's. I've read quite a few accounts of BCM uppers needing substantial left adjustment and it keeps being blown off as "a shooter problem" or a "rear sight problem".

Well the guy is admitting to being new to the AR platform. And we want to work off facts as much as possible since these things have a way of taking on a life of their own.