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Mossberg 930 Autoloader Troubleshooting

Discussion in 'Mossberg 930 Autoloader' started by DHonovich, Sep 3, 2010.

  1. Jmm14534

    Jmm14534 20g Supporter Premier Member

    Messages:
    507
    Looking for feedback from fellow 930 owners.

    I noticed that my field and clay 930 has a inconsistent “hard to load” issue. By this I mean that every so often the shell I’m loading into the tube requires a harder push to get it into the tube. It’s like the shell is fat and requires significantly more push.

    I spent the fist half of last nights football game inserting and unloading a few different makes of shells to try and understand what’s going on. The quick unload feature comes in handy when doing something like this.

    What I found was when you place the shell on the lifter (gun is upside down with trigger guard up and vertical) and gently push the round down and forward into the mag tube it is much more likely to get “stuck” then if you aggressively slam the shell down and forward into the mag tube. In fact when I used the aggressive technique I did not experience a “hard load” scenario.

    I then pulled out my other home defense 930 and tried the same test and the results where similar.

    Any other 930 owners with a similar phenomenon?
    Last edited: Oct 15, 2021
  2. waz0wski

    waz0wski .22LR

    Messages:
    10
    My 2017 SPX was like this, my latest 2021 JM isn't.

    Can you tell if the hangup is from the lip of the tube, or from the shell stop? Any physical issues like burrs on the lip mag tube, an issue with how it's cut & beveled, or a shell stop that's not positioned right could cause this behavior but you'd likely see it during normal operation too.

    On my SPX, it appeared to be an issue with side-to-side slop in the trigger and lifter assembly - I could push down on the lifter and the whole assembly would shift until the edge of the lifter popped into the slot on the underside of the charging-handle side of the slide assembly dropping the lifter a bit more and reliably causing shells to hang up on the lip of the tube. Slop in the assembly seems to be common on the 930s, and IMO can cause unnecessary wear or issues with the shell stop. I ended up putting a couple strips of HVAC tape on the inside of the receiver, charging handle side, to tighten it up. An extended lifter also prevents it from happening - but you lose the ability to clear double feeds from the bottom
  3. Jmm14534

    Jmm14534 20g Supporter Premier Member

    Messages:
    507
    For those interested. I took waz0wski’s advice and looked into it. Yes there is some trigger assembly slop left to right. Not much but with the bolt forward there is a small amount. On the gun I was looking at it was not enough to keep the shell lifter from going into the relief slot at the bottom of the bolt.
    I decided to take the trigger assembly out and see it the “fat shell” phenomenon was still a thing. Bottom line is that with the trigger assembly out I could insert a shell at any angle I could come up with and no problems.
    Did I mention that I had an aftermarket mag tube follower installed? I decided to go back to the stock Mossberg follower to see if this made a difference. Low and behold no more fat shells!
    I have my suspicions regarding the aftermarket market follower and I will reach out to the manufacturer to provide my feedback for what it’s worth.
    Problem solved!
  4. TheRude1

    TheRude1 .270 WIN

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    262
    What kind of follower is it?
  5. Jmm14534

    Jmm14534 20g Supporter Premier Member

    Messages:
    507
    MCARBO.
  6. PSU_WPG

    PSU_WPG Copper BB

    Messages:
    1
    I have about 200 rounds through 930 pro series waterfowl. There is scarring/grooving on the magazine tube in the general location where the gas piston assembly rests (picture attached). I have had some failed cycling issues with both trap loads and magnum waterfowl loads. I have thoroughly cleaned the entire assembly after 100 shots and 200 shots. This is my first mossberg auto and the amount of fouling was a lot compared to other gas operated autos I have run. 2 questions; I plan on upgrading the spacer with a OR3GUN option, do I need to deal with the grooving on the magazine tube prior to doing anything else? Is it normal to have extensive fouling after 100 shots?
    magazine tube.GIF
  7. Jmm14534

    Jmm14534 20g Supporter Premier Member

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    507
    I’ll let you know when I get another 60 or 70 rounds thru my 930. I am looking to do the first disassembly, inspection and cleaning once I hit the 200 round mark.
  8. waz0wski

    waz0wski .22LR

    Messages:
    10
    Which shells and what kind of cycling failures?

    Tough to see scratching in the picture, I don't see anything abnormal compared to my 930s. If your mag tube surface is rough you could clean and polish it before installing the OR3Gun MST. Some people have reported earlier in this thread that the mag tube getting scratched by burrs on the secondary gas spring inside the gas cylinder. If that's the case, you can polish up the tube and file/polish the burrs off the spring without removing.


    Fouling in the cylinder/piston area is normal and time before it starts causing problems and cleaning is required depends on the type and quanity of shells you run. The OR3Gun MST should help with fouling and cycling. For high-volume shooting the SBE Precision piston is another good upgrade to help with this, however I'm not sure they're produced anymore.
  9. Zakk

    Zakk Copper BB

    Messages:
    4
    Attempting to install an urbino stock I was tempted to remove the two screws above the recoil tube. Out pops this little guy which I’m assuming is part of the safety. It’s now impeding my recoil system and not letting me get the bolt back. How does it go back together?

    Update: I've come to understand that its the bolt buffer assembly. Mine looks like someone has beat it with a small hammer every day for 5 years and is still locking the follower in the tube stopping the bolt from moving.

    Attached Files:

    Last edited: Nov 7, 2021
  10. Jmm14534

    Jmm14534 20g Supporter Premier Member

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    507
    Zakk. That looks nasty and not normal. From the first pic it looks like there is more of that nasty surface finish forward of the buffer assembly. Did you buy your 930 new or used? If you purchased it new I would contact Mossy service and get the to replace it.
  11. Zakk

    Zakk Copper BB

    Messages:
    4
    Just send them an email with the same photos attached. Hopefully I can just get the part sent to me, but its not listed for sale anywhere I can find so I have a feeling it will be complicated. Got it new from PSA recently, haven't shot it yet.
  12. Jmm14534

    Jmm14534 20g Supporter Premier Member

    Messages:
    507
    My experience with Mossberg service has always been positive. You’ll probably have to ship the receiver back to them. Maybe the whole gun. The buffer assembly is one of those parts they don’t sell.

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