Bolt not always locking back on last round?

Discussion in 'Rifle Country' started by beagler, May 3, 2021.

  1. BillWM

    BillWM Member

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    So0me springs in magazines only should be assembled one way. Possibly if the spring is the other way round it is not pushing the rear of the follower up enough to engage the hod. Or a weak spring not quick enough? Can you push the follower down with your finger and release it, does it move fully upwards?
     
  2. beagler

    beagler Member

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    I am able to move the spring on all the mags. The followers do move fully upward as well. I know there are several tricks others are doing with their mags for the 350. There seems to be a common occurrence with jamming and the 350.
     
  3. beagler

    beagler Member

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    I received the upper today back from BCA. They touched up/polished the feed ramps on the barrel and fired 10 rounds without issues. I put the upper on a home built lower and loaded 3 rounds in a DuraMag. Next, I took it outside and fired them as fast as I could. No jamming, perfect ejection, and the bolt locked back on the final round. I hand cycled 9 additional rounds between 2 different mags with no issues.

    BCA was very fast and responsive to my concerns and appeared to fix the issues. They handled all the shipping to and from them for free. Total warranty process took 2 weeks from the initial email to them to today. Bravo BCA!
     
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  4. chicharrones

    chicharrones needs more ammo

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    13 rounds down the tube. Thousands more to follow. ;)
     
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  5. ColoradoMinuteMan

    ColoradoMinuteMan Member

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    Good news. Was that the same lower you had the initial issue with? I’d be interested if it made a material difference to the original issue.

     
  6. RCB

    RCB Member

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    Sounds like they got it fixed for you. I had some feed issues similar. One was due to being sent the wrong buffer in the right packaging (SRS) and the second was the mags just bring funky. I had flipped the spring to keep pressure on the front of the follower and then filed a few jagged edges which resolved my feed issues.
     
  7. beagler

    beagler Member

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    Yes it was the original lower.
     
  8. ColoradoMinuteMan

    ColoradoMinuteMan Member

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    Cool. Despite it making very little sense, it seems like it worked. I wonder if they did a little more than they said (like checked and fixed the gas block or port).
     
  9. beagler

    beagler Member

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    Right? I’m confused as well. Oh well, it seems to function now.
     
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  10. herrwalther

    herrwalther Member

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    Glad the trip back to BCA fixed the problem. For whatever reason polishing the feed ramps worked this time. I would keep an eye on it just in case the issue pops up again down the road.
     
  11. beagler

    beagler Member

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    This is the reason why I get my new hunting rifles ready well before deer season. I want all the bugs worked out well before opening day. I’m not even mounting a scope on it yet. I’ll run it through it’s paces with flip up sights for now.
     
  12. beagler

    beagler Member

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    Another update:
    I wanted to keep this going for anyone following. I shot 22 rounds today with one failure to feed. So that is one failure in the last 35 rounds. I really like this caliber and my new AR. Hopefully I’ll get more range time soon.
     
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  13. beagler

    beagler Member

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    Update
    Ran 20 rounds of WW 145 through it today to sight in a new scope. No issues except the bolt did not lock back on one empty mag. I’m just happy it’s feeding and ejecting well now. 55 rounds down the pipe since BCA sent the upper back to me. It shot well at 50 yards. We will keep shooting it.
     

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  14. Riomouse911

    Riomouse911 Member

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    Keep your Mags marked so you can determine if one or mare are also causing issues. I use a drop of model paint or black sharpie and mark mine like dominoes; 1 dot on Mag 1, 2 dots on Mag 2, etc.)

    When you have a bum Mag it’s easy to either work on that one or replace it :thumbup:.

    Stay safe.
     
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  15. Skylerbone

    Skylerbone Member

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    I have 3 rifles chambered for 350 Legend, one using AR style magazines. Came with and ordered additional Duramags. That particular rifle being a turn bolt, I didn’t have last round hold open to worry about but I did have multiple gremlins.

    After examining brass, I began with the feed lips which were leaving striations. Disassembled the magazines and gently sanded with 320 grit until the feed lips no longer resembled razor blades to the touch.

    Still had feed issues. Rounds were jamming during cycling. I removed my magazine and began stripping cartridges by hand, noting that often the case mouth would contact the front of the magazine. I whittled at the front of the magazine until I had 100% reliable feed both by hand and with the rifle.



    44BA00A6-6FCA-4AC4-9C92-57E1DB8F305E.jpeg
    Above showing modified magazine (with round pushed forward to show relation).

    8978094F-D4A0-4802-8A3B-8173F4FD8298.jpeg
    As received factory magazines.

    18E0DFFD-E865-410A-B793-5CC4C4E06DAC.jpeg
    Side by side.

    I am not an expert in all things AR; I have shot several for a decade or more and assembled a few. I do whole heartedly agree that feed ramps can in no way interfere with lock back. Not ever. If all that’s been done to your rifle was a polishing of the ramps, your hold open isn’t fixed.

    I would hunt down a second manufacturer’s magazine to test. I would also weigh the buffer just for fun and find out what others are using. Lastly, though first in actual order, would be to make sure the rifle is correctly lubricated. I got so wrapped up in a pistol build once that I neglected to oil anything. Fired 2 rounds, had to mortar both out, then my brain finally came through for me.

    Best of luck.
     
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  16. beagler

    beagler Member

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    Thank you! I will check my Dura Mag out and see if I have similar issue as you did. I appreciate the detailed response.
     
    Skylerbone likes this.
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