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Thread: Help - Weird New Double Feed LMT

  1. #1
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    Help - Weird New Double Feed LMT

    So I've got around 2500rds through this LMT MRP. Currently suppressed. All have been flawless (besides a bad extractor that was replaced early on). Today, I went to the range and experienced what looked like a weird double feed with several different magazines pretty frequently, and once while driopping the bolt on a fresh mag. See pic. Both rounds are live and unfired.



    The bottom round pops up and catches the bolt during it's forward travel, and keeps the top round from chambering. This was the same malfunction every time it happend. Always two live rounds. I thought magazines, but it happened with gen3 pmags, Okay Ind. USGI's, and a buddy's DD mag (5 different mags in total). All these mags worked fine previously in multiple rifles. When evaluated, sometimes the hammer was cocked, other times it was not.

    Ambient temp was 18F. I used an H3 buffer with Geissele braided wire spring and a carbine buffer with a Tubbs Flatwire spring today. Both allowed the malfunction to happen. I used an H2 with the Geissele braided wire spring for most of the previus rounds before today. But the first 300rds today were fine with the h3 as well. I applied more lube. Still malfunctioned.

    After the last rounds of the day were fired, I noticed the pistol grip was loose. I tightened it down and applied locktite. I don't know how this could have possibly caused double feed malfunctions. Becasue my ammo ran dry, I could not test.

    Any thoughts?

  2. #2
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    just curious: is it a quality buffer tube that’s properly screwed in and staked?

  3. #3
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    LMT buffer tube, staked.

  4. #4
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    I think your problem is in the buffer tube.

    Finally became a noticeable problem at 18F.

  5. #5
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    Quote Originally Posted by 17K View Post
    I think your problem is in the buffer tube.

    Finally became a noticeable problem at 18F.
    What would be wrong with the buffer tube? If you mean literally "in" the buffer tube, I find it odd that it would run fine for 300rds first, then wouldn't run suddenly with two different spring/buffer combos of pretty drastically different weights. Also, I've shot it fine in pretty similar conditions previously. If it's spring related, how would that casue the second round in the mag to nose up?

  6. #6
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    Do the LMT rifles have adjustable gas system?
    Are you having the problem unsuppressed?


    Sent from my SM-N975U using Tapatalk

  7. #7
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    Quote Originally Posted by omegajb View Post
    Do the LMT rifles have adjustable gas system?
    Are you having the problem unsuppressed?


    Sent from my SM-N975U using Tapatalk
    No adjustable gas system. Yes, malfunction occurred both suppressed and unsuppressed.

  8. #8
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    Quote Originally Posted by Hox013 View Post
    No adjustable gas system. Yes, malfunction occurred both suppressed and unsuppressed.
    Well, there goes my idea. Good luck.

    Sent from my SM-N975U using Tapatalk

  9. #9
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    Quote Originally Posted by Hox013 View Post
    What would be wrong with the buffer tube? If you mean literally "in" the buffer tube, I find it odd that it would run fine for 300rds first, then wouldn't run suddenly with two different spring/buffer combos of pretty drastically different weights. Also, I've shot it fine in pretty similar conditions previously. If it's spring related, how would that casue the second round in the mag to nose up?
    Something with those springs and buffers isn't playing nice with the rest of the gun if it isn't the mag. Something is causing the bolt to bounce during the feed cycle or somehow making the mags burp.

    The only thing it can be other than that is bad mags or slamming it in too hard on a bolt locked reload.

    Because a true double feed is the magazine. The bolt can't reach down in there and scoop out two rounds.

    If you send that rifle to LMT, the first thing they'll do is rip all that stuff out of the buffer tube, replace with correct parts, and money says 'could not replicate'.
    Last edited by 17K; 02-14-20 at 18:47.

  10. #10
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    Quote Originally Posted by 17K View Post
    Something with those springs and buffers isn't playing nice with the rest of the gun if it isn't the mag. Something is causing the bolt to bounce during the feed cycle or somehow making the mags burp.

    The only thing it can be other than that is bad mags or slamming it in too hard on a bolt locked reload.

    Because a true double feed is the magazine. The bolt can't reach down in there and scoop out two rounds.

    If you send that rifle to LMT, the first thing they'll do is rip all that stuff out of the buffer tube, replace with correct parts, and money says 'could not replicate'.
    I'm going to go back to the h2 configuration that has worked and bring a tripod. I'll see if I can get any slow enough video to catch anything. This just doesnt make sense, it was fine for 2200rds and the pistol grip just happened to also be loose? Seems too weird to be coincidence to me. Might leave the h3 and just try shooting it again now that to grip is secure again.

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