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Thread: Odd jam...Any ideas?

  1. #11
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    When a malfunction occurs, do you always try to figure out why it happened, or do you apply immediate action to clear it?

    I clear the stoppage immediately and drive on. I do not try to analyze a malfunction, unless it has happened more than a few times.

  2. #12
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    Maybe you had a blown primer that was wedged in their. When you dropped the mag it could have fell out and maybe you didn't notice it. Kinda had the same thing happen to me with a surefire socom can and some over pressured 5.56 ammo. Primer was stuck above bolt and didn't allow bolt to go into battery.
    People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. - George Orwell

  3. #13
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    Quote Originally Posted by WS6 View Post
    Thanks!
    Do you think it could have been a bolt-bounce issue, somehow? I would think the round would still have been nabbed under the extractor, though?

    Shell-casings were ejecting to about 1:45. Normally without the can, it ejects to about 3:45.
    Ejecting at 1:45, plus not fully in battery. Sounds like a short stroke IMO

  4. #14
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    Quote Originally Posted by sdw308 View Post
    Ejecting at 1:45, plus not fully in battery. Sounds like a short stroke IMO
    But the round was almost fully chambered? 10.5" suppressed gun short stroking milspec ammo using h2 buffer and usgi spring?

  5. #15
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    Any problems before using Froglube?

    H

  6. #16
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    Quote Originally Posted by WS6 View Post
    But the round was almost fully chambered? 10.5" suppressed gun short stroking milspec ammo using h2 buffer and usgi spring?
    If the bolt was far enough rearwards that it picked up the new round, it should have enough potential energy to chamber a round...something slowed or stopped it. This is assuming that your spring is still in spec and that it was well lubed.

    Bolts don't come forward with any extra force if they went backwards super hard...once it stops, it only has the force of the action spring pushing on it and the buffer, and once they're moving you gain the momentum of the buffer and BCG.

    So yes, it's safe to say that short stroking isn't your problem. I'd measure your action spring and see what you get.

  7. #17
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    Quote Originally Posted by thopkins22 View Post
    If the bolt was far enough rearwards that it picked up the new round, it should have enough potential energy to chamber a round...something slowed or stopped it. This is assuming that your spring is still in spec and that it was well lubed.
    It is, it was.

    Bolts don't come forward with any extra force if they went backwards super hard...once it stops, it only has the force of the action spring pushing on it and the buffer, and once they're moving you gain the momentum of the buffer and BCG.
    I agree. I think the Noveske lower plus the Lancer mag was the issue. The round probably nose-dived. Lancer mags do that with out of spec lowers if they don't insert far enough and only the bottom of the lugs strip the round. I'll have to use PMAGs in my Gen 2 Noveske lowers I believe. That's what I attribute it to thus-far is a nose-diving round that BARELY made it out. On my other Noveske, sometimes they would just jam half out of the mag, maybe once every 3-400 rounds on a reload when the bolt-rease was used on a fresh mag, although sometimes now that I think of it, I do recall it "feeling odd" cycling a time or two. Every time I tried to duplicate it, it would chamber the top round in the same mag, even if I BARELY dropped the bolt, much less from full lock-back. Stumped. Sometimes it did...sometimes not. Then I compared what part of the bolt was hitting the back of the casing to a known high quality mil-spec type lower from Daniel Defense.

    So yes, it's safe to say that short stroking isn't your problem. I'd measure your action spring and see what you get.
    I think this is the issue, and here is a picture. I have owned 2 of these Noveske FFL Gen 2 lowers and they are both the same. Compared to my Daniel Defense and other in-spec guns I have seen, they place the mag further down and the bolt doesn't hit the back of the case as squarely. I have personally seen it cause issues while training with my carbine before, like I said, on reloads when I hit the bolt-release, although not in live fire until maybe now? Easily could have caused a nose-dive and a stopping/slowing of the BCG, IMO.

    Here is the Noveske compared to the Daniel Defense that I took a while back diagnosing THAT issue. I think it may have caused this one, too.


    Last edited by WS6; 08-19-13 at 10:56.

  8. #18
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    Quote Originally Posted by WS6 View Post
    I think this is the issue, and here is a picture. I have owned 2 of these Noveske FFL Gen 2 lowers and they are both the same. Compared to my Daniel Defense and other in-spec guns I have seen, they place the mag further down and the bolt doesn't hit the back of the case as squarely. I have personally seen it cause issues while training with my carbine before, like I said, on reloads when I hit the bolt-release, although not in live fire until maybe now? Easily could have caused a nose-dive and a stopping/slowing of the BCG, IMO.

    Here is the Noveske compared to the Daniel Defense that I took a while back diagnosing THAT issue. I think it may have caused this one, too.
    I think this is likely it. I encountered a similar "strange" issue a few months back on a buddy's gun. I had him put some Federal 62gr Fusion soft points in the mag (also a Lancer L5 AWM) so I could see if the nose was impacting the feed ramps at and extreme angle or maybe even the front of the magazine. He was using some shit-brand lower but it was the same issue. I could see the nose of each round was smashed to hell (but ti didn't do anything to the nose of the '193 rounds). Didn't happen with USGI mags with MP followers (Brownells mags).

    Also, the L5 AWM's in my experience, apply more pressure on the bottom of the BCG due to their extra-stout mag spring. This could also exacerbate the issue by artificially slowing the Carrier's final stroke, going into battery due to friction of the round body against the interior of the feed lips. I think IG's rec on the Blue spring and H3 buffer may alleviate any issues that are purely related to the Lancer's XP mag spring.
    "That thing looks about as enjoyable as a bowl of exploding dicks." - Magic_Salad0892

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  9. #19
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    Quote Originally Posted by thopkins22 View Post
    If the bolt was far enough rearwards that it picked up the new round, it should have enough potential energy to chamber a round...something slowed or stopped it. This is assuming that your spring is still in spec and that it was well lubed.

    Bolts don't come forward with any extra force if they went backwards super hard...once it stops, it only has the force of the action spring pushing on it and the buffer, and once they're moving you gain the momentum of the buffer and BCG.

    So yes, it's safe to say that short stroking isn't your problem. I'd measure your action spring and see what you get.
    This problem may still be short stroking. The bolt not only needs to come back far enough to clear the rim, it needs travel back enough that the bolt gets a running start before it contacts the new round. If the bolt stops just as it clears the rim, it won't have any momentum to strip the next round. Spring pressure alone may not be enough to reliably feed the next round. It will be worse with aluminum mags, especially with steel cased ammo because aluminum mags have more stiction.

    Of course, as you point out, a weak action spring will also cause this issue along with giving the rifle sharper recoil
    INSIDE PLAN OF BOX
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  10. #20
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    Quote Originally Posted by MistWolf View Post
    This problem may still be short stroking. The bolt not only needs to come back far enough to clear the rim, it needs travel back enough that the bolt gets a running start before it contacts the new round. If the bolt stops just as it clears the rim, it won't have any momentum to strip the next round. Spring pressure alone may not be enough to reliably feed the next round. It will be worse with aluminum mags, especially with steel cased ammo because aluminum mags have more stiction.

    Of course, as you point out, a weak action spring will also cause this issue along with giving the rifle sharper recoil
    ARs just don't have that much over travel, so the bolt starts running forward and then has the additional friction of striping a round out of the mag to cope with almost immediately.

    There just isn't a lot of margin in the AR's energy budget when compared to a AK or other rifles.

    H

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