Sights not aligned (?)

[Sharpshooter]

Okay, I'm a relative newbie with the black rifle. I've used them a bit, a long time ago, but never had to monkey with repairing or adjusting them significantly. So here's my issue:

I bought a new DPMS MOE model. Sighting in, it was shooting to the right by about 6 or 8 inches at around 50 yards. I cranked the rear sight (Magpul BUIS) all the way to the left and got it to hit about 1 or 2 inches to the right, still at 50 yards. So I took some masking tape, put a couple of pieces on the handguard at front and rear, set my combination square to give me a line near the center of the handguard, then marked it off on both left and right sides, front and back. Then I laid a straightedge on the marks and took some pics. As far as I can see, the front sight is way off to the right.

If this was a bolt gun, I'd just drift the sight over and get it lined up. But I don't want to screw up this rifle before I've had a chance to really get to know it. So, any help you guys could offer would be most welcome. Pics below. I know the pics don't show the rear pieces of tape, but trust me, the straightedge is aligned properly.

Edited July 31, 2018 by Sharpshooter

[DNP]

Post a pic of your rear sight. I made a mistake with mine and I have a hunch. 

[Sharpshooter]

Sorry for the delay. Also, sorry for the poor quality of the pics. I'm not a good photographer.

I appreciate any input you may have.

Thanks!

[DNP]

Not what I was thinking I'd see. My dad installed his backwards and I never noticed it was wrong. We couldn't get it to sight in and we're having a similar experience. Once it was pointed the right way...all was good. 

Did you buy that BUIS seperate, or did it come with the rifle?

[survivalshop]

 New Rifle , contact DPMS for Warranty work .  They are bad photo's , hard to tell , I think you need more light , maybe take a photo outside . The Rear sight or Receiver ,seems to be cocked to one side . You might want to remove the Hand Guards to get a better view of the Gas Tube & Barrel , it may help in determining what is going on .

This is how I checked a Factory Colt that was sightly out of alignment.  Using a Laser.

 

Edited August 1, 2018 by survivalshop

[Doodle]

Try removing the rear sight.  It may not be seated in the pic rail properly.  Check the rail where it was seated for burrs or divets.  Also check the underside of the removed rear sight to see if the pic rail engagement bar(s) are level, bent, or have some debris in there.  Reseat rear sight in same place if all looks good and also try reseating the rear sight up a couple notches on the pic rail and compare.  

 

Edit to add:  Also try installing the rear sight backwards and see if it leans the other way.  Then you know its the sight, not the rail or upper.

Edited August 1, 2018 by Doodle

[HotRod308]

To get the rear sight center and have the rifle hit where you aim zero windage without any wind blowing. The front sight needs to rotate .008 for every inch off at 100 yds. When moving the front sight to correct windage it's the opposite direction of the rear sight, in your case the front sight needs to rotate to the right to move the muzzle to the left.

But doing this it would look pretty odd by how much it's off. I would agree that if it's a brand new rifle the barrel could of made very wrong and there is no way to correct it.

But there is one last thing to check. Your rear sight is a clamp on. You have to make sure it's actually physically canter on the receiver with windage set at zero. I found on my nightforce scope mount it fit perfect on one of my DPMS uppers perfectly square and level, but on another upper it would not. It was cooked not level and was unable to level the scope in the mount or use on that rifle. The reason was the machine of the clamp didn't fit the edge correctly and was clamping on the unmachined surface instead of the sharp edge of the flap top. the machine work of nightforce wasn't at fault neither was DPMS it just didn't work out.

 

Edited August 2, 2018 by HotRod308

[HotRod308]

After looking closer at your photo it does by appearence that the front sight assy is leaning way to the left visually which would make sense why the rifle is shooting way to the right. So I would assume the front sight is pined to the barrel is not adjustable, so the barrel extension was over tighten on to the barrel when it was put together and chambered.

Just a guess.

Edited August 2, 2018 by HotRod308

[98Z5V]

On 8/2/2018 at 4:55 AM, HotRod308 said:

 So I would assume the front sight is pined to the barrel is not adjustable, so the barrel extension was over tighten on to the barrel when it was put together and chambered.

Just a guess.

In barrel manufacturing, that barrel extension installation/torqueing is on of the first operations. That's what determines barrel centerline. After that, when headspace is good, the rest of the barrel is completed (gas port drilled, etc.)  It wasn't that the extension was overtorqued, not in this case.   Chances are good that it's a taper-pinned FSB, and it wasn't centered on the barrel when they reamed it and pinned it.  It's off center now.

OP, there's not much that DPMS will be able to do for you, in that case, besides replace the barrel.  The can't ream it again, and re-pin it with taper pins. That's just not possible.  They would have to start with a new barrel that hasn't been reamed yet.  If you want to fix this yourself, you can.  Even if it's way off, is the barrel shooting well?  If so, save it. Fix it at home.

You could do this with it, if you wanted:

 

[mrraley]

you might want to try and loosen the barrel nut a little to see if there is any play from the index pin in the upper also.