Help me diagnose my goofy AR issue

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  • Tactically Fat

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    And then you can rail on me for not having the money for better parts.

    That said:

    Took both of my AR rifles down to a little slice of paradise in Brown County on Saturday, along with a buddy and his rifle, in order to sight-in A) his new LWRC + Vortex Razor 1-6 and B) my home-build + Vortex PST 1-4. I also took along my "red dotted" rifle to plink with as well. My rifles will now be referred to as "RD" for Red Dot and "Scoped" for the, ahem, scoped one.

    As said, this scoped one is a home-build. Anderson lower, upper, BCG, barrel. Probably an Anderson LPK, too, but I honestly cannot remember the brand of LPK. RD rifle just also happens to be an "Anderson Optic Ready" rifle - but with lots of mainly cosmetic mods. BCG, barrel, upper, lower, etc are all still Anderson.

    Scoped rifle: Upon insertion of a loaded mag into the rifle with a closed bolt: The CH (BCM, by the way) retracts, bolt goes forward to strip a round, and that round is fully chambered as far as I can tell. This round will then also fire - but it will not extract all the way. The CH of this rifle is now difficult to retract and usually needs the aid of a hard surface to tap the butt-stock on in order to extract.

    This is the same issue with the factory brass ZQI XM855 ammo that I have, same with my buddy's brass 55gr Prvi Partizan, and with my gracious host's brass 55gr reloads.

    NOW: This rifle will run JUST FINE and as intended with by swapping the BCG for the one that normally lives in my RD rifle. Due to this, definitely don't think it's a gas issue. (Also, I believe that I put the "bad" bolt in the RD rifle - and also had issues - but I honestly cannot remember for sure)

    SO: What's wrong with this scoped' rifle's bolt / BCG? What should I look for when I have a chance to really examine this rifle's bolt? Should I just tear down the bolt, clean/lube, reassemble, and then try it again?

    Now you can A) help me, and B) make fun of me for only having an Anderson budget.
     

    T.Lex

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    I will not participate in the (B) part of your request, in that I respect living within one's means. :)

    On, (A) do you know the specs on which BCG is which? I know you said "Anderson" but I'm not familiar enough with their products to know if they have different spec'd BCGs.
     

    churchmouse

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    I have some Anderson uppers floating around in some of my rifles. Never an issue.
    I had exactly the same issues with my 10.5" AR on Saturday. It ran fine before I swapped out the BCG on the last shoot I attended (not sure why but it must have been important) and now it will fire the 1st round and gets jammed up in the ejection cycle.
    I did not swap in another BCG as yet. I did increase the gas supply and put new rings in the BCG.
    Will have to wait and see if this solved anything.
     

    rvb

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    Scoped rifle: Upon insertion of a loaded mag into the rifle with a closed bolt: The CH (BCM, by the way) retracts, bolt goes forward to strip a round, and that round is fully chambered as far as I can tell. This round will then also fire - but it will not extract all the way. The CH of this rifle is now difficult to retract and usually needs the aid of a hard surface to tap the butt-stock on in order to extract.

    what if you don't fire it? Just chamber, then try to extract?

    -rvb
     

    gmcttr

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    If this is a new rifle/bcg, I would attempt to warranty the bcg.

    If it's an older 'out of warranty' rifle that worked well previously, check to make sure the bcg's gas key is still securely fastened and check the bolts gas rings to make sure all three are still there and in good condition. Makes sure there is not excessive carbon build up on the bolt and in the bcg as well. Is the Extractor and it's spring still in good condition, cleaned and oiled? Might as well check that the bolt cam pin is not cracked while you have it apart.
     

    M67

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    How old of an Anderson lower? Is your buffer getting chewed out by the buffer detent?

    Slice of paradise in brown county.....yeah....that right there would get you a rail instead of the AR issue
     

    Tactically Fat

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    what if you don't fire it? Just chamber, then try to extract?

    -rvb

    I honestly don't remember. I'm a pretty poor story teller. :(

    If this is a new rifle/bcg, I would attempt to warranty the bcg.

    If it's an older 'out of warranty' rifle that worked well previously, check to make sure the bcg's gas key is still securely fastened and check the bolts gas rings to make sure all three are still there and in good condition. Makes sure there is not excessive carbon build up on the bolt and in the bcg as well. Is the Extractor and it's spring still in good condition, cleaned and oiled? Might as well check that the bolt cam pin is not cracked while you have it apart.

    The BCG/Bolt were purchased last winter, assembled sometime early this year. First time firing it was this past Saturday. Gas key is definitely still staked - and staked well.

    How old of an Anderson lower? Is your buffer getting chewed out by the buffer detent?

    Slice of paradise in brown county.....yeah....that right there would get you a rail instead of the AR issue

    The lower is now pushing 2 years old. No issues that I can tell on the buffer end of things. Before we put the "good" bolt in the "bad rifle", we swapped the buffer - still same issues. Swapped back to the originals.
     

    gmcttr

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    From the diagnostic steps you have taken, it certainly seems that the problem is with the bcg so either warranty/replace it or take the bcg and bolt apart, even though this was only the first firing, and look for the problem. I've have gas rings sheared off (probably got pushed out of place when the bolt was inserted into the carrier) on a bolt with very little use.
     

    Trigger Time

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    If you get around beech grove I'll be happy to look at it for you in person and help you with, of coarse
    free of charge for a fellow ingo'er. Pm me if so.

    i won't make fun of you. I don't blame you for buying what you can buy at the time
     

    Tactically Fat

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    From the diagnostic steps you have taken, it certainly seems that the problem is with the bcg so either warranty/replace it or take the bcg and bolt apart, even though this was only the first firing, and look for the problem. I've have gas rings sheared off (probably got pushed out of place when the bolt was inserted into the carrier) on a bolt with very little use.

    I will note that, at least upon casual observation, nothing jumped out as "goofy" when the BCG was removed and looked at. It'll need broken down and compared to a known good one for sure.

    If you get around beech grove I'll be happy to look at it for you in person and help you with, of coarse
    free of charge for a fellow ingo'er. Pm me if so.

    i won't make fun of you. I don't blame you for buying what you can buy at the time

    I'll bring my Old Fashioned mix. :D I'll let you know, man. Thanks!
     

    seedubs1

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    1) Remove upper from lower. Does the BCG easily slide in and out by hand or is it getting hung up on something?
    2) Swap components of the BCG. You've already swapped BCG's and confirmed the BCG is malfunctioning. Do big components first. Is it the bolt or the carrier?
    3) This is why you don't skimp on the BCG. BCM, DD, Noveske, Sionics, Colt, LWRC, Sharps, Youngs, etc... It's the heart of your AR, and it's only $20-40 extra to get a true known quality mil-spec BCG. Eat ramen if you have to.
     

    Mgderf

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    My nephew had some failure to extract issues this weekend.
    His Anderson AR was sheering off just enough of the case rim off to leave the case in the chamber.
    This in turn, caused the next round to get jammed into the receiver when it was still being held in place by the magazine feed lips.

    He was understandably upset.
    This was basically a new AR. I'm sure it had less than 500 rounds down the pipe, and it is a factory build he purchased at Rural King.

    This was during our annual family Fathers day shootout, held at his fathers house.
    I got the first stuck case out of the chamber with a cleaning rod.
    When the next case did the same thing I told him to let me see it.
    Took the upper off, removed the bolt and charging handle.
    Inspection of the bolt showed brass shavings.
    I looked into the bore and saw it was dry as a bone.

    I asked my nephew if he forgot to lube this thing after he cleaned it last.
    He said, "No, I'm sure I lubed it."
    I asked him if he oiled the bore and chamber. He said he ran an oiled patch down the barrel.
    I used the cleaning rod and a patch to swab a bit of Hopp's gun oil in the bore and what do you know.
    It started running like it was supposed to!

    I think he learned a valuable lesson, and at a good time.
     

    lovemywoods

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    The BCG appeared to be well-oiled so I don't think that was the issue this time.

    I looked at the BCG. It was well staked. The bolt would move into the carrier with some resistance. It would pass the "stand it on end and the bolt shouldn't move into the carrier". However we didn't take the bolt apart and inspect the rings. Interesting idea.

    I'm looking forward to seeing what the INGO brain-trust and Tactically Fat come up with.
     

    halfmileharry

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    I'll go back to "WET" again. I've seen some new weapons needing more than normal lube until they get a few rounds through them to be dependable. I don't like it but it's even happened to me on a couple of high dollar weapons.
     

    IndyGlockMan

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    I agree with Trigger Time...
    Swap in a different charging handle and see if that makes a difference.
    When you remove the bolt and charging handle, check the inside of the upper along the top where the charging handle rides and see if there's any damage, scrapes, or gouges - abnormal wear.

    Is the bolt/carrier group nickel-boron coated?

    might just have to scrap that carrier and get another.
    odds are, the bolt is probably fine, but the carrier could be out of spec, but probably best to scrap the whole thing if it keeps failing in different rifles.

    I've built and used lots of Anderson parts and they have all been fine.
     
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