Diamondback DB7 Still Issues with Alignment for ZERO MBUS and VORTEX SFII

New post but old problem on still new gun. First, link from initial find on the alignment issue from when I bought the gun new and posted on here.
https://www.ar-15.co/threads/153775-...h-MBUS-Problem


After alignment on top rail was correct I had not went back to the range till past Monday with a co-witnessed Vortex Strikefire II and my MBUS. This gun is still new and never hit paper as of yet. I should of laser bore sighted Monday before going to Magnum but I didn't as I thought I would hit 10 yards and walk it out. No go.. no paper at all from red dot or MBUS. So, here I am again now that I'm focused back on this weapon and the issue here.

After my attempt to hit paper at Magnum Monday I came home and did what I should of in the first place. Laser Bored Sighted both VORTEX and MBUS. I can't live with that MBUS that far off as its not normal at all. So, I coordinated with a secretary at Diamondback yesterday and this morning as I was wanting or trying to talk with a smith. She seems to be stalled with what type of ammo I am using and such. But maybe they will eventually help.

Here are my photo's and I ask for your thoughts on this... First two pictures are original from COAR15 Forum years ago. Last photo is current now that I have bore sighted VORTEX and MBUS. Zero I'm sure but not acceptable. I'll never be happy with the MBUS this far off center and I did swap the rear MBUS out but didn't help.

So, "COLLET" ? maybe?

Thoughts please.

https://www.dropbox.com/sh/h90vaq55k...K8lgP7b5a?dl=0

2 observations...
1. From the pictures of your rails, the hanguard does not appear to be indexed properly with the upper
2. I would question the barrel installation

If I owned the rifle, it would be headed to Bowers Tactical for Rob to take a look at.

Quote:

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Originally Posted by 20X11

2 observations...
1. From the pictures of your rails, the hanguard does not appear to be indexed properly with the upper
2. I would question the barrel installation

If I owned the rifle, it would be headed to Bowers Tactical for Rob to take a look at.

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I agree, also suspecting there is a problem with the barrel or the installation of the barrel. My guess is the barrel is not indexed correctly.

If it's under warranty, I think you should really push for the manufacturer to look at it.

Otherwise, you might see something by examining it yourself. Check to see if the barrel nut was overtorqued and broke or bent the index pin. If that's the case, you can reassemble with a new pin and the proper torque. If the pin looks right, you may need to swap barrels and just see if the new one solves the issue.

Quote:

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Originally Posted by Little Dutch

I agree, also suspecting there is a problem with the barrel or the installation of the barrel. My guess is the barrel is not indexed correctly.

Just called Bowers and was told first come first serve. That is great as I am 1.10 hrs away. So, I'll need to get that down and see what they can do and I'm sure it will be better then Diamondback as they have now responded and said send it in and maybe six weeks. I don't have that kind of patience.

Thanks 20X11 and Little Dutch. I appreciate the FORUM members here very much.
v/r
Mike

If it's under warranty, I think you should really push for the manufacturer to look at it.

Otherwise, you might see something by examining it yourself. Check to see if the barrel nut was overtorqued and broke or bent the index pin. If that's the case, you can reassemble with a new pin and the proper torque. If the pin looks right, you may need to swap barrels and just see if the new one solves the issue.

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6 weeks is a loooong turnaround time.

Keep us updated.

All good now. Rob is the man and a walking encyclopedia on gun smithing. I'm impressed and many many thanks guys. Brought it home, bored sighted the MBUS and Vortex and all happy. Range time next Monday I hope at Magnum.

Happy to have helped out.
Just make sure to sandbag or equivlent support, and evaluate iron sights and optic seperately, so we can minimize variables.
Though i did reinstall the barrel, its so short for caliber, i wont be happy till you tell me its shooting correctly.
Thanks for coming by with it, and i hope to hear soon that all is working correctly

There you are... thanks Rob and I will do my best to go shoot her next Monday. I'll let you know and I'll be around.

Quote:

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Originally Posted by FireMoth

Happy to have helped out.
Just make sure to sandbag or equivlent support, and evaluate iron sights and optic seperately, so we can minimize variables.
Though i did reinstall the barrel, its so short for caliber, i wont be happy till you tell me its shooting correctly.
Thanks for coming by with it, and i hope to hear soon that all is working correctly

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Good stuff.

Rob, just a heads up... just PM'd you. I took this long to get back to the range today and this gun is a mess. Going to need to leave it with you I would assume and get to the bottom of this.

Quote:

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Originally Posted by FireMoth

Happy to have helped out.
Just make sure to sandbag or equivlent support, and evaluate iron sights and optic seperately, so we can minimize variables.
Though i did reinstall the barrel, its so short for caliber, i wont be happy till you tell me its shooting correctly.
Thanks for coming by with it, and i hope to hear soon that all is working correctly

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Ok, range today which is first trip since my last visit in Apr and a trip to see Rob at Bowers which again was great. This damn DB7 AR is a sick puppy. After my visit with Rob I bought a nice Bushnell boar sight and actually measured off 23 meters in my back yard to boar sight the exact distance I would be shooting. Today at Magnum, I popped off three rounds supported with my red dot. Nothing on paper. I sent it back to 23 meters and popped off three more with my MBUS and again nothing on paper. Pulled it in and I'm just in disbelief at this point since I boar sighted I should be close. Sent it out to 10 meters to at least work with windage and popped off three rounds and barely caught paper at 9 O'clock. Needed to come in about 12 clicks right. Moved in about half distance of what I needed. Six more clicks and the rear windage is now moving pretty much very far right but the bullet impact went in the other direction back toward 9 O'clock and up just a few clicks. Range master suggested the rear MBUS may be bad. He brought me in a brand new rear MBUS and I installed it and send my target out to ten meters again. I caught paper at 9 O'clock. I run it 6 clicks to the right to start in the right direction for windage and it moved up! As you can see, this DB7 is crap. I hate this and it’s the first in my lifetime that I've had a bad gun. Looking forward to talking with Rob and bring it in in hopes he can pinpoint the issue/issues and I sure I’ll need to leave it with them.

In Rob's post on the first page he says he remounted the barrel, but also commented that the barrel is so short for the caliber. What caliber is it and what is the barrel length ?

Colorider, its a 5.56/223 Multi with a 7.5 inch barrel. I have two twins. This one is sick and the other is perfect. I wish I new about the short barrel issues prior to purchase as I would of went with 10 or so.

Quote:

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Originally Posted by colorider

In Rob's post on the first page he says he remounted the barrel, but also commented that the barrel is so short for the caliber. What caliber is it and what is the barrel length ?

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I hope this does not sound like a problem other then a gun issue. I'm only trying to determine to move on to a new barrel if that is the fix.

Finally got back to focusing on this problem child Diamond Back DB7 AR. New barrel... problem solved. Zeroed yesterday and it works flawlessly. Good to go.