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Thread: Gun sluggish/problems chambering in "cold"

  1. #1
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    Gun sluggish/problems chambering in "cold"

    Looking for some explanation of what's going on here and why, as well as the solution. I have a feeling it's simple, which has made me hesitant to ask about this, but as with anything else involving firearms, I know if I'm having this issue then someone else is too.

    When the temp drops a bit here in the Houston area to what we consider to be a "little cold," which is in the 40's and 50's (Northerner's feel free to insert smart ass comments and jokes here), sometimes my guns have issues clambering a round when I'm either initially making ready or performing a speed reload.

    For example if I hit the bolt release on a fresh mag of 28 rounds the bolt gets stuck halfway and only chambers 1/4 of the round. Obviously charging the gun will induce a double feed so I'll either strip the mag and try again (in which case it'll likely happen again with the next round) or I'll pull the CH back a half inch or so several times as need to finally shove the rest of the round in the chamber. Once I get most of the way the forward assist can be used if necessary. Then I commence firing.

    Sometimes though, from there even though it gets shoved into the chamber the damn bolt doesn't even grab ahold of the round's rim, so it's literally loose in the chamber. Although that rarely happens.

    Even manually charging the guy when reloading a full mag, whether it's from a closed or open bolt, it'll get hung up halfway sometimes.

    This literally only happens in the cold, with the exception of one time when my gun was completely dry because I forgot to lube it on TD 2 and 3 in my recent TAPS class and dirty as hell with almost 4K rounds, some suppressed, through it.

    But other than that one time, my guns are always nice and wet with Slip 2000 EWL. Always. I added some lube to my already-wet BCG/CH/Upper a few weeks ago when this happened, and it did seem to help barely get the job done, but even without a mag inserted and just racking the CH back and forth it seemed so damn sluggish. My friend was also with me and was shooting my other gun (both guns are BCM 14.5 mid-lengths, but this has happened in the past with 2 SBRs as well), and it had not even 500 rounds on it yet and felt mostly the same, once again it was nice and wet, too.

    And although it may just be coincidence, this only seems to happen after the sun sets at night (I shoot a lot at night) in the 40's/50's (doesn't usually get colder than that), not during the day even if the temp is the same.

    So wtf is going on here? Possibly mags? It's also occurred with brand new GI mags as well. I went ahead and changed the RE spring/buffer spring on the gun with 4K rounds, even though it was only a half inch shorter than a new BCM one. Try a different lube other than the Slip 2000 EWL?
    Last edited by RetreatHell; 01-19-12 at 03:03.
    S/F
    Paul

  2. #2
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    What brands of parts are you using?
    "Not every thing on Earth requires an aftermarket upgrade." demigod/markm

  3. #3
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    On the primary carbine I'm talking about its a complete BCM lower, H buffer, buffer spring bought from BCM, BCG BCM and 14.5 middy upper BCM as well.... So yeah, a few BCM parts!

    BTW mags were PMAGs.
    Last edited by RetreatHell; 01-09-12 at 17:16.
    S/F
    Paul

  4. #4
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    FYI here is a vid I made last week or so showing how nasty the gun was before I cleaned it. Boring vid really, but skip to 1:40 to start getting an idea of condition of the gun.

    http://www.youtube.com/watch?v=tkpEl...e_gdata_player

    Maybe I should start occasionally taking the whole BCG out so I can squirt plenty of lube into the whole upper instead of just locking to the rear to lube? I dunno. Seems like such a stupid ass lame problem though.
    S/F
    Paul

  5. #5
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    Even the most super duper sythentic lube will thicken when cold.

  6. #6
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    Quote Originally Posted by dpaqu View Post
    Even the most super duper sythentic lube will thicken when cold.
    Yah but 40-50 degrees Fahrenheit?

  7. #7
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    Yep, it happens.

    You already said you had the BCG good and lubed so that's Part 1. Part 2 I have never advocated until I experienced the same issues as you described several times: lube the action spring/buffer/inside of the receiver extension - take your pick.

    I've never told people to lube this area before (and I never did it before either) but it seemed to work to keep my gun stripping that first round off and chambering it consistently. Guns that have done this to me include Colt 6920 and DDM4 with NHMTG 30 round aluminum magazines loaded to 28 rounds.

    Cold, wet weather usually does it, 30's and 40's.

  8. #8
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    Good to know, thanks for the info, brother. Nice to know I'm not crazy or weird after all

    I'll give that I try next time I'm out in the frigid Houston winter temps.
    S/F
    Paul

  9. #9
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    Seems to me that it doesn't have enough spring tension to reliably cycle in all conditions.

    4k is getting up there on spring cycles and it is probably borderline weak.

    Try releasing from full recoil vs bolt stop to see if there is any difference.

    I'd try replacing it with a new spring to see if that resolves the issue.

    Lubricating the spring may work, but I don't feel that is the best way to restore proper operation.

    I may do some tests with various springs to determine the minimum distance the bcg must be retracted to properly chamber a round.

    My A5 was able to do it with the front edge of the carrier lined up even with the center of the port door.
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  10. #10
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    Measure your free spring length.
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