G36 Barrel nut loosening when firing
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Thread: G36 Barrel nut loosening when firing

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    Default G36 Barrel nut loosening when firing

    Anyone else ever have this issue. I just put a brand new K barrel on my new to me G36, and after just a couple mags the barrel must was coming loose, twice. Both times I used the mandrel and wrench to tighten it down. First time torqued to 35 second time to 55, and it still came loose on me.

    Am I supposed to put grease or anything on the threads? It’s a brand new barrel

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    No grease or anything on the threads required. I have never heard of this happening before. Are all parts factory German HK? Your torque should be fine.
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    I've read that it was 66 lbs to torque.

    35 was probably too light to begin with but 55 should've been ok.

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    You need to remove and clean the threads thoroughly. Torque specs will only be reached on dry threads (no oil or grease whatsoever), or would specify a much higher torque spec and denote the lubricant to use. No barrel nuts use lubricant or antiseize to my knowledge.

    That said, your barrel wrench AND mandrel are the right tools for the job, and I've never had a problem when getting it just "gutundtight". Don't be afraid of it, and recognize that the barrel nut threads onto a steel trunnion that is held by your mandrel - a very strong mechanical interface.
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    Pretty sure at least some of the ones put on at factory used Loctite, as they took considerable force to remove even after they were initially broken loose. The armorer's manual does not say they used Loctite, but there was definitely something on the threads. However, it DOES say it should be torqued to 66 lb-ft. It is extremely tight, and you won't be able to do it without damaging the receiver if you don't have the proper tools. I had a few on demilled receivers and had only made the nut wrench, and the trunnion broke the receiver before the nut came loose.
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    Quote Originally Posted by AviatorDave View Post
    Pretty sure at least some of the ones put on at factory used Loctite, as they took considerable force to remove even after they were initially broken loose. The armorer's manual does not say they used Loctite, but there was definitely something on the threads. However, it DOES say it should be torqued to 66 lb-ft. It is extremely tight, and you won't be able to do it without damaging the receiver if you don't have the proper tools. I had a few on demilled receivers and had only made the nut wrench, and the trunnion broke the receiver before the nut came loose.
    I think the SL8's did at one point.
    docwade likes this.

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    Soooo figured it out. I using an Inch Pounds Wrench and not a Foot Pounds wrench...smdh didn’t even think to look, I committed assumicide. Used a ft lbs wrench to 25lbs and put 5 mags through it, zero issued

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    Quote Originally Posted by Reaperatm View Post
    Soooo figured it out. I using an Inch Pounds Wrench and not a Foot Pounds wrench...smdh didn’t even think to look, I committed assumicide. Used a ft lbs wrench to 25lbs and put 5 mags through it, zero issued
    I applaud your honesty. But, why 25? Even the low end of the spec is 60, and many recommend 45.

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    That’s what Tom Bostic tightens his too. Honestly, I’m new to the G36 platform, and 25lbs feels very tight

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    Quote Originally Posted by Reaperatm View Post
    That’s what Tom Bostic tightens his too. Honestly, I’m new to the G36 platform, and 25lbs feels very tight
    Copy that. Thanks

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