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Mossberg 930 Autoloader Troubleshooting

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

  1. Jspencer09

    Jspencer09 Copper BB

    Messages:
    4
    I'm gonna say it's on the tube where the piston rests, there is some imperfections that I think need to be cleaned up, found a couple Burr's on the shell tube. Gonna clean it up today and try her out this week. Thanks for the insight

    Sent from my SM-G920P using Tapatalk
  2. Jspencer09

    Jspencer09 Copper BB

    Messages:
    4
    Decided to clean and recheck, still having firing issues and not seeing contact on the brass end so I'm figuring it's a bolt issue. Gonna contact Mossberg tomorrow and see what they want to do.

    Sent from my SM-G920P using Tapatalk
  3. DasPomPom

    DasPomPom Copper BB

    Messages:
    2
    I bought a GG&G combo sling adapter and flashlight mount for my pretty new 930 security with 2-round Choate extension tube. But every 16-24 rounds either the spring it follower would bind and only partially expel the next round out if the magazine tube. Removing the adapter solved the problem.

    GG&G customer service confirmed my suspicion that the adapter creates a gap between extension and magazine threads where the spring or follower may get hung up. They suggested a few possible fixes.

    1. I checked the spring and it's fine.
    2. There's a tiny dent in the magazine tube where the threads are, but given that it functioned fine without the adapter, I don't know if it's the problem, or it's not the problem alone.
    3. Cleaned and lightly oiled the magazine tube, follower, and spring.

    I have a range session coming up, so we'll see if that fixed the problem. If not, I decided to Tacticool it up with the Black Aces quad rail, which will make the adapter obsolete anyway.

    Just a report for anyone else who has had similar issues.
    Last edited: May 9, 2017
  4. 10Andrew

    10Andrew Copper BB

    Messages:
    7
    Was looking to post new thread, but didn't find. Question is: Looking for as many ways as possible to insure 930 Home Defense is free of Failure to Extract. I think this would cure any other problems. Not having that many now that it's clean and oiled, but just want as many ideas on the fte as I will take it apart again soon. Thanks
  5. OR3GUN

    OR3GUN Sponsor Sponsor

    Messages:
    218
    There is a lot of information already in this thread, but 71 pages is a lot to wade through for a simple list of things to look at.

    1) Ensure you have a smooth chamber. This will open the range of options and make problematic shells less sticky on the way out.

    2) Avoid shells with aluminum bases and hulls that easily deform when pinched. These will expand and grab onto your chamber. (See #1)

    3) Run your gas system dry and your bolt/slide (carrier) wet with lube. Lube in the gas system tends to gum things up quickly.

    4) Thoroughly clean your gas rings, separate from the piston every time you clean the gun. This will keep the 930 running at its best.

    5) LFS (Look for Stuff) whenever you take your 930 apart. Scoring on the magazine tube, buildup under the shell stop assembly, abnormal wear. Catch them early and address the cause before they become something that causes malfunctions. Spring burrs and rough part machining can wear into the gas system and cause leaking. The same can be said for the recoil system. Burrs on the recoil spring can prematurely wear the plunger and return spring tube.

    5) Tune your 930 for the loads you will be running. The ability to run 3" magnum loads that you will never use will make running 1145 FPS target loads frustrating. If you have no use for light loads, make sure your 930 is fortified to run the heavier stuff.

    We have a lot of parts that will help with this process, though many of them are specialized for competition. As you can see, a lot can be done to improve reliability before investing in parts. Once you head down that road, look us up.

    William

    http://www.OR3GUN.com
  6. 10Andrew

    10Andrew Copper BB

    Messages:
    7
    OR3GUN, Thanks for condensing 71 pages. I printed your post and will use it as a guide next time I disassemble my 930. Been considering ordering your OR3GUN MST blue spacer too.
  7. OsteKuste

    OsteKuste .22LR

    Messages:
    17
    If you are talking about that small ring, it goes in a thin groove under the heavy spring before the gas piston. If you pull the piston out and look you can barely see it. I called Mossberg and they wanted me to send it back for the experts to fiddle with, took me five minutes to figure out. I think I caught mine with the end of the mag tube during reassembly. Now I'm more careful. Sorry if I misnamed any parts, this is my first autoloader.
    MrSluggo likes this.
  8. BrassnDust

    BrassnDust Copper BB

    Messages:
    2
    With my Mossberg 930 spx I have only shot around 200 shells through the 4 weeks of owning it, every time I remove the barrel to clean it the gas piston scratches the tube really rough, I have I emailed Mossberg and they told me that it was normal. Has anyone been having the same problem?
  9. OR3GUN

    OR3GUN Sponsor Sponsor

    Messages:
    218
    While it is not entirely uncommon, it is not 'normal' and can lead to issues down the road.

    What you have is a burr on either your secondary gas system's seal ring or on an end of the large, heavy spring that lives in the secondary gas system. Depending on where in the assembly the burr is at, high power loads that cycle the secondary gas system can scratch and score the section of the magazine tube where this system cycles, every time it cycles. This can quickly lead to a poor seal of the secondary system, allowing gas to leak around the magazine tube and secondary seal ring. It then becomes the path of least resistance in your gas system. This gas will then not be available to cycle lighter loads, even if the secondary is not opened by the pressure of the load.

    This secondary gas assembly requires special tools to remove/replace because of the heavy spring pressure in the assembly. Once done, you only need to file and polish the burrs and it won't continue to scratch the tube. If it is only scratching when the barrel is removed/replaced it is not scoring an area that is used to seal the secondary and it is the forward most end of the spring doing the damage. This is less of an issue for keeping the gun running reliably.

    If you don't have any luck getting Mossberg to perform the work for you after determining where the burr is at in the system and explaining the issue in detail, send us a PM. You could send us only the barrel and we do have the proper tooling to remove/replace the secondary gas system. Mossberg should fix it for free, however.

    William

    http://www.OR3GUN.com
  10. BrassnDust

    BrassnDust Copper BB

    Messages:
    2
    Thank you, I let Mossberg know the information you gave me and they accepted my shotgun for repair. Hopefully they can fix the problem with the gas piston as well as either replace the tube or fix it since the gas piston messed it up. I will give an update when I receive my shotgun back to see what they have done.
    UPDATE
    I have received my shotgun back, they replaced some of the internals and the magazine tube, when I took my shotgun apart the gas piston started to scratch the magazine tube again, but it was not grinding on it like before, the only issue I have now is that it still scratches but they are not deep, you cant feel it when you run your finger across it, mostly like a surface scratch. I contacted them again and told them I was having the issue again, they told me this is to be expected with this model of shotgun. Other than that its great to know Mossberg stands behind their firearms.
    Last edited: Feb 28, 2018
    OR3GUN likes this.
  11. Lefty9

    Lefty9 .270 WIN

    Messages:
    241
    Jolly Good show !
  12. Mccarlson

    Mccarlson Copper BB

    Messages:
    5
    Why is it doing this? I have a brand new Mossberg 930 I purchased as a home defense shotgun. The problem is that it came with a "JAM MY GUN BUTTON" that I didn't know about. That button is the bolt release button. If you have shells in the feed tube, then press the bolt release button at any time, two shells (more if they could fit) will eject from the feed tube into the chamber, jamming up the shotgun, essentially making it useless. This occurs when the gun is in ANY position, with all brands and sizes of shells, at any part of the loading cycle, with a brand new non-modified factory stock gun, with 100% repeatability every time. Needless to say, I'm kind of pissed. I took it to a local gunsmith and as soon as I showed him the issue, he didn't even want to deal with it and just told me to send it to Mossberg. That's how messed up this is.
    VIDEO HERE!

    Edit 7/24/2020 I received a reply from Mossberg:
    "Mike, From what I could see in the video, the gun is working as it was designed.
    Sincerely,
    Customer Service Team
    O.F. Mossberg & Sons, Inc."

    Well, just don't touch that button in a tactical situation I guess.

    Last edited: Jul 24, 2020
  13. OR3GUN

    OR3GUN Sponsor Sponsor

    Messages:
    218
    Agreed, the bolt release should perform ONLY that job. This is why our Enhanced Bolt Release has an overtravel stop built into it. This was to minimize the possibility of activating the 'quick unload' feature of the 930 and the resulting double-feed that occurs. It's a simple fix, once you realize it needs to happen.

    http://or3gun.com/OR3GUN/about_or3gun_release.htm

    They have mostly addressed the issue on the 940, as they adopted our skirted button design for the 940 JM PRO version. You will have to use the 930 version for yours with a set screw as the 930 is not drilled/tapped for a universal button and is a hardened part.

    William

    http://www.OR3GUN.com
    meanstreak likes this.
  14. Frank McCarthy

    Frank McCarthy .410

    Messages:
    86
    Honestly, mine will do the same thing. As OR3GUN said, it's a "quick unload" feature. You're supposed to hold the gate up before you push the bolt release button. This was so you didn't have to cycle the bolt over and over to unload it. It tells you how to do it in the manual. I've had mine for years and it's never been a problem.
    meanstreak, Sarge and Pawpaw like this.
  15. Rob72

    Rob72 .410

    Messages:
    86
    It is not a "feature," its because they kept the cost down by not adding Benelli's shell release lever.

    I trimmed down a GG&G bolt release to fit inside the Beretta 1301 bolt release shroud. It should work with the Aridus Industries aluminum shroud, but that's substantially more expensive. I posted a pic on the SBE Piston thread.
  16. Army_of_One

    Army_of_One Copper BB

    Messages:
    5
    Well, I'm sending my 930 JM Pro in. Stupid charging handle is stuck! Before anyone jumps on me, I have a 930 SPX that the handle comes out of like it's supposed to. Sucks waiting 6 to 8 weeks for something so simple.
    meanstreak likes this.
  17. Sarge

    Sarge .22LR

    Messages:
    16
    Agreed on all counts. We've got two 930s and neither of their bolt releases have pushed themselves. There's a learning curve for everything mechanical.
    meanstreak likes this.
  18. Rob72

    Rob72 .410

    Messages:
    86
    The bolt release functions when impressed forward, the shell-dump/release functions when the button is pressed towards the rear. Whether or not this is an issue depends on your use. Comparable tactical shotguns do not allow this "feature," Benelli M1-4, Rem 1100 Tactical, FN-SLP, and the now revised Beretta 1301. Adding the shell-drop lever was an early modification to the Benelli M1 to keep it from crapping it's pants when bumped against a door jamb, or had the receiver pressed between the user's chest and thigh, in a crouch.

    Not having the cut-off for the automatic shell dump, on a shotgun billed as "tactical", is a cost-saving measure, nothing else. I know of at least one County Department that would not consider the SPX for that reason (not that Mossberg was high on the list, as they were under Remington contract, and had the budget for Benelli, but even so...)

    If you want the shell dump on a bird gun or 3-gun, cool. For your HD/bug-out gun, not a bonus.
    meanstreak likes this.

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