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Thread: Tons of bolt-over-base malfunctions...help

  1. #51
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    It looks like you have a combination of 2 or 3 problems.

    -Upper with a high bore axis

    -Lower with sloppy front-back fit that wont fit any other uppers.

    -Sharp "lug ways" in the feed ramps.


    I took a look at 8 different barrels / barrel extensions I have on hand.

    Each one is slightly different.

    There must be a bunch of different mfgs.

    You can feel the difference between a "good" and "bad" extension when holding a loose round parallel to the bore and running the nose up the feed ramp.

    If the corners of the "lug ways" in the feed ramps are parallel and sharp, they will trap the nose of the round, creating resistance.

    Its unmistakeable.

    If the "lug ways" in the feed ramps are opened up near the top, the round will slide up freely.

    You can see this on your DD extension. My BCM is the same way.

    More mfgs should pay attention to this small but important detail.

    Apparently BCM and DD do.


    If you choose to fix it yourself, the good news is you can knock off the corners in 5 minutes with the barrel removed from the upper.

    Take 5/32" and 7/32" chainsaw files and snap the tips off so the grit goes completely to the tip.

    Use the larger one first and finish with the smaller.

    Short, plunging strokes with heavy pressure seem to work well, just like a broach.

    Make it look like the DD.

    Check with a loose round.


    This should make the feeding more reliable, even with the low and nose-diving rounds feeding from the mag.

    Quote Originally Posted by WS6 View Post
    So, I began googling this issue. Apparently, it's pretty common.
    I came up with this video:
    https://www.youtube.com/watch?v=jevZBNUbg1o

    So, I went to look at the feed ramps in my Noveske (lots of FTF), and my Daniel Defense (Never an FTF.)

    ...

    I believe this to be the issue. Depending on how bad the teeth dig in, is how bad the rifle functions. The more violent the action cycles, the harder that round hits those teeth, the more they dig. This explains why with the H buffer I had less issues than the H2 buffer. It explains why the jam is erratic. It fits.

    That said, I am still confident that Cold will make good on his offer to do his best to get my lower fixed so that it's in-spec, if indeed it is out of spec as Daniel Defense reported to me. Also, I am sure that if this barrel extension is the issue, something will be done about it. If it's not too much to hope for, the 8MOA POI shift will also be addressed which causes me to have to nearly bottom out the FSP to zero irons with the can on. Just updating the thread with what I had found so far.
    Last edited by Clint; 12-07-13 at 22:24.
    Black River Tactical
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  2. #52
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    It's a complete noveske product and needs to go back for the other issues, as well. In future circumstances, I agree, but I'm not going to dremel on a $1600 upper that's a warranty issue.

  3. #53
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    Excellent thread, full of knowledge and what if's?

    There are times when stacked tolerances create borderline issues (sporadic performance) in this case.

    What I have learned from this exchange is that I have a gas problem in my rifle, not an out of spec one.

    Clint, I almost broke out the dremel!

    Thanks for sharing your issues, and waiting to hear out it works out.

  4. #54
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    No Dremels! Way too aggressive.

    I don't even own one.

    A sharp file is plenty to knock the corners off.
    Black River Tactical
    BRT OPTIMUM HFCL Barrels - Hammer Forged Chrome Lined 11.5", 12.5", 14.5"
    BRT OPTIMUM Barrels - 16" MPR, 14.5" MPC, 12.5" MRC, 11.5" CQB, 9" PDW
    BRT EZTUNE Preset Gas Tubes - CAR and MID
    BRT Covert Comps 7.62, 5.56, 6X, 9mm
    BRT MarkBlue Gas Tubes - BRT EXT, EXC and PDW Lengths
    BRT MicroPin Gas Blocks - .750" & .625"
    BRT MicroTUNE Adjustable Gas Blocks
    BRT CustomTUNE Gas Ports

  5. #55
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    Clint, Very good observation on the chamber end of the feed ramps...

    I use craytex with a fordom, but a file is safer and slower..

  6. #56
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    I used Craytex and a Dremel and polish the ramps and break the lugs in the path of the feed ramps.



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  7. #57
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    have they gotten back to you from you contacting them?

  8. #58
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    Quote Originally Posted by wsaraceni View Post
    have they gotten back to you from you contacting them?
    Last week on Wednesday, Cold from this thread told me that he would make sure they would. He and I spoke for about half an hour, but I have not yet heard from them, otherwise.

  9. #59
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    Quote Originally Posted by Clint View Post
    No Dremels! Way too aggressive.

    I don't even own one.

    A sharp file is plenty to knock the corners off.

    OK, not kidding this time, all the corners top and bottom, or what are we really looking at here?

    Thanks

  10. #60
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    OP I had a friend that bought a DD upper during the panic and he was having the same issues you describe. Lots of failures and lots of ammo was fired in different combos with known working guns making sure it was the upper. He contacted DD and they fixed it very quickly and without any hassle.

    It was the barrel extension that was out of spec. DD figured it out right away.

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