Weird AR fail.

Discussion in 'Rifle Country' started by Trey Veston, Apr 27, 2021.

  1. Trey Veston

    Trey Veston Member

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    Took my new AR pistol to the range to sight in the red dot and everything was fine at 25 yards...

    IMG_20210427_140300628_HDR.jpg

    But I noticed I was having some light strike issues and rounds weren't cycling. Figured I'd just need to get it home and clean it.

    Moved back to 50 yards and got one shot off and the action locked up. Couldn't cycle the bolt back more than half-way and the trigger was completely locked.

    IMG_20210427_142034929_HDR.jpg

    Took it down in the field and discovered what had gone wrong...

    IMG_20210427_142321563_HDR.jpg

    The buffer tube retaining pin and spring had come out somehow and lodged in the trigger mechanism.

    Never seen that happen before. I had removed the brace to install a sling attachment plate, so I must have done something wrong when putting it back together. Had to take it home to get the spring and pin out and everything back together, so need to go back and verify it's working and finish sighting in.

    Anyone else had weird failures like that?
     
  2. adcoch1

    adcoch1 Member

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    I would bet your receiver extension tube needs to be threaded in further. That is a weird one though....
     
  3. WestKentucky

    WestKentucky Member

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    At least it was easy to diagnose. My wierd one was that I would shoot a round and the gun would cycle, and then for the next shot I got a click and when I would go to put safety on it would fire. That took a while to figure out. Lower out of spec... my 80% so I couldn’t complain but it was hard to figure out.
     
  4. Trey Veston

    Trey Veston Member

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    Upon reassembly, I did thread it in further, so hopefully that was it.
     
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  5. Ritchie

    Ritchie Member

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    As I recall, the buffer tube is supposed to retain the buffer tube retaining pin, with just enough clearance to let it be pushed down.
     
  6. taliv

    taliv Moderator Staff Member

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    What’s up with the face on that hammer?
     
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  7. 7mmsavage

    7mmsavage Member

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    Was wondering the same thing. At first I thought that was the issue, until I saw the spring all bound up down there. Looks like it’s been burned and hit really hard by the firing pin or something. Does back pressure from suppressors cause that kind of marking?
     
  8. WhoMe?

    WhoMe? Member

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    If the new receiver end plate is too thick it can prevent the buffer tube from screwing in far enough to retain the pin and spring. And if the buffer tube is already a hair short or the retainer hole is just a bit forward you can quickly run into tolerance stacking issues.
     
  9. DustyGmt

    DustyGmt Member

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    I like the POF anti tilt buffer tube. I never heard of carrier tilt and don't even know if it's a benefit to a non piston AR, but what I do like about it is it's 7075 and has a lil recess cut into the threaded end of the tube to shroud the buffer spring retainer so there is no possible chance your buffer tube can rotate and cause this or other malf's, the retainer button literally has nowhere to go and the tube has no way to rotate out of place.

    I'm pretty sure it allows your buffer tube to have a few more threads engaged into your upper for added rigidity.
     
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  10. BigBore44

    BigBore44 Member

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    My brother had a strange failure one day when we were shooting with his police issue Bushmaster. Loaded a round. Bang. And then a FTF (feed). Close, but no cigar. Hits the forward assist. Nada. Dumped the mag and tried to eject the cartridge, it’s stuck. Boot trick. Worked. Cycle it, dry fire, cycle, dry fire. Good to go. Load in another mag, drop the bolt release, failure to fully chamber. Drop mag, try to cycle bolt, it’s stuck again. Boot trick worked. At this point we decided to completely field strip it. And that’s when we discovered a complete 223 neck in the chamber. Factory Hornady ammo. Remove the embedded neck, and we were back in business.
     
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  11. jmorris

    jmorris Member

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    I have also seen a primer fall out and work it’s way under the trigger becoming a “safety” that required disassembly of the trigger group to fix.
     
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  12. AlexanderA
    • Contributing Member

    AlexanderA Member

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    Gas is blowing back past the firing pin. The firing pin hole may be oversized, or you may have defective gas rings.
     
  13. oldschool45

    oldschool45 Member

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    I made that whoopsie with not threading the buffer tube far enough in on my AR pistol. Fixed the retaining pin with a spring from a ball point pen. I had bad ammo that was making me neurotic with cycling issues.
     
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  14. Wreck-n-Crew

    Wreck-n-Crew Member

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    Funny this thread should come up. I had what i thought was an issue with my 300 blacout loads not properly cycling. I cleabed the gun well inckuding the BCG. So i loaded up a set of loads that are subsonic and hit the range. Normally i shoot heavy 225-230gr bullets slightly on the supersonic side.

    I get to the range ( no target needed after all its just a cycle test ) with 2x30 rnd mags. But somethibg was different .

    With the lighter loads i notice it sometimes was not extracting. Odd. Extractor looked good. Held on to empty brass well so i threw it back in and finished the loads off and headed home.

    So when i got home i figured i would take the extracror off, clean it and insect it as well as the ehector.

    2 light taps on the extractor pin and half of it fell out! Extractor remained with the ither half of the pin holding it in.

    I guess you could say this is not uncommon as parts do break on AR-15's. But this pin had me flustered.

    Needless to say i ordered a few of them so i would have at least one spare between the 2 AR-15's i have.

    20210428_180559.jpg
     
  15. Elkins45

    Elkins45 Member

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    I’ve had the same as the result of poorly swaged primer pockets on surplus brass.
     
  16. herrwalther

    herrwalther Member

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    That certainly is weird. I have seen lots of AR malfunctions but that is a first for me. Are you using any non standard parts like castle nut extension, exotic endplate, or something like that?
     
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