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I have a bunch of parts that I got just before everything went nuts, so I started building. I noticed that my lower is too tight so I backed off the jam ring on the barrel nut. Which created another problem. Now when I thread on the handguard, there is a gap between the barrel nut jam ring/handguard and the lower. I was thinking about sanding down the take down pin pocket on the lower. That seems to be what is causing the issue. Anyone got any ideas how to move forward?
 

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Can you explain what you mean when you say your lower is too tight? Not sure what you are referring to.
 

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For some reason my old account was on my tablet.

If I have my barrel nut jam ring tight up against the upper, the pins don't line up. It looks like it might be the barrel nut itself too. Not sure if sanding down the take down pin pocket (front) on the outside of the lower where it is rubbing the barrel nut/jam ring/handguard area is the right move. Franklin Armory upper, Anderson lower.
 

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What you seem to be saying is there seems to be a little too much "meat on the bone" so to speak . I'm reading it as you are saying that if the boss around the pin was a little less beefy the nut would fit farther back . If you are set on that nut and ring set up and don't want a gap you can file the boss down a little and paint with a sharpie ,if it's not too much . Of course you don't want it to be too thin/ weak to support the weight of the upper when shot gunned down for cleaning etc. Install the upper and measure the gap and you will know how much you will have to take off . Or you could sell nut and get one that fits.

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Is it the actual barrel nut contacting the lower or is it the handguard lock ring? If you thread the lock ring as far as it will go towards the receiver it probably will hit the lower.
 

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Looks to me like the lock ring that is hitting. What is the make of that hand guard?
 

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The pin pocket actually hits the barrel nut and the jam ring. In that first pic, the jam ring is threaded a little short of the upper. I really just think that the lower front pin pockets are f'd up. I bought it from outdoor sports. I've built a few like this (same parts for all 3-4 of them) and haven't had any problems.
 

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I advise against sanding or altering any parts before completely diagnosing the issue.

Have you fired your rifle with it like this? Do you or anyone else think it could be a safety issue?

I have been following this thread because I have the same issue on my 6.8 after I had a new APR barrel installed by a gunsmith. At first the upper could barely tip forward, not enough to remove the BCG. I took it back to the smith. When I got it back that time, it would only tip forward about 35°. I took it to another gunsmith (I think I can trust?) and it is been at his shop for several months now along with a bolt action rifle that the safety stopped working on. I have been thinking about picking it up and start searching for yet another gunsmith in Phoenix.
 

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I am willing to lay odds that if you changed hand guards and use one that doesn't use that locknut you would solve that problem. I never cared for those personally and I can see where it can cause many problems.
 

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I know it was asked earlier, but what manufacturer is the handguard system? I personally haven't seen a locknut system like that, I'm no expert just would like to learn about the manufacturer.
 

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In my case, the same handguard was used with the previous barrel without issue.
 

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The photo below shows the barrel nut and jam ring from a Midwest Industries handguard product that was assembled to the adjacent Mega upper receiver by H in September of 2011 (forgive the dust).

The gap between the barrel nut face and the centerline of the receivers' takedown lugs is a function of
1) the applied barrel nut torque,
2) the fabrication performed by the manufacturers of both the upper and lower receivers,
3) and the thickness of the barrel extension's flange as machined by the barrel extension manufacturer.

The second photo in post #7 leads me to believe that the lower receiver manufacturer got sloppy with casting/fabrication processes.

If I were in your situation, I would pull the barrel and measure the thickness of the barrel extension flange to see if it is within milspec. Assuming it measures within tolerance, I would stone the shiny surfaces down until they no longer make contact with the barrel. Significant linear forces can develop as a result of the rotational contact. The use of power tools is not advised.

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