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Help!! 930 wouldn't cycle 3" shells

Discussion in 'Mossberg 930 Autoloader' started by Yanger, Oct 27, 2018.

  1. Yanger

    Yanger Copper BB

    Messages:
    7
    Hi everyone,
    I have a very confusing problem.
    I brought this 930 used. The gun can cycle 2 3/4 shells no problem.
    I have tried 7 1/2 target load, buckshots and slugs. The gun cycles them no problem. However once I start using 3" waterfowl shells it would not feed them from the magazine. I have rounded and polished the shell stop following the brownell article. I can manually cycle the 3" shells without problem.
    I have done the following tests
    Chamber 2 3/4" and 3" in the magazine that would cycle.
    Chamber 3" and 2 3/4" in the magazine that would cycle.
    Chamber 3" and 3" in the magazine that would not cycle.
    The magazine is plug for only 2 rounds and I have tried taking out the plug and filling up the magazine with 4 rounds of 3" still wouldn't cycle.

    The magazine tube doe have a few light marks on it.
    I'm wondering is my next step to replace the magazine or keep trying different ammo hoping the gun will find one it likes and cycle it??

    Any advice or suggestions would be greatly appreciated

    Andy
    meanstreak likes this.
  2. John A.

    John A. I'm "THAT" guy Staff Member Global Moderator Moderator

    Messages:
    13,308
    Does the shotgun seem to be cycling very hard with the 3 inch shells? Since you said you can manually cycle/chamber the 3 inch shells, that would appear to show that the chamber will accept them without a problem.

    Reason I ask how the gun is cycling is I wonder if the previous owner may have replaced the factory spring with a lighter one and am wondering if it's battering the bolt and cycling too hard.
    meanstreak likes this.
  3. Yanger

    Yanger Copper BB

    Messages:
    7
    The 3" has harder recoil than the 2 3/4" but I don't find it abnormally harder than say buckshot or slugs.
    I want to add that extradition is very good.
    The 2 3/4 or 3 shells will fly out and land 3 to 4 feet away.
    Could the problem be the bolt is going so fast and hard that it doesn't trip the shell stop leveler?
    meanstreak likes this.
  4. John A.

    John A. I'm "THAT" guy Staff Member Global Moderator Moderator

    Messages:
    13,308
    I wouldn't be able to guess, but is something that I would check.

    I have a Charles Daly MaxiMag 12 gauge that I have replaced the main spring in order to get it to cycle 2-3/4 inch shells since they're mainly what I use.

    The shotgun is actually set up for 3 and 3 1/2" shells, so it definitely had a strong spring originally and was just too strong for the 2 3/4's. So, I used a lighter spring so it will allow the weaker shells to cycle the bolt properly.

    I know with other guns, if the spring is too light, will also cause feeding problems. As well as battering the bolt and receiver. And with your 930 being used, it's untelling what has been done to it by a previous owner.

    I'm only speculating what it may be.
    meanstreak likes this.
  5. Yanger

    Yanger Copper BB

    Messages:
    7
    Thanks for the suggestion.
    So my options are
    Mag tube replacement and recoil spring replacement.
    I'm wondering if there is anyway to adjust the secondary gas system?
    meanstreak likes this.
  6. OR3GUN

    OR3GUN Sponsor Sponsor

    Messages:
    199
    The secondary gas system doesn't really have any way to adjust it, unless you have access to specialized tools and springs from earlier versions.

    It is very likely the magazine spring. The heavier shell column is being pulled away from the shell stop (and proper feed timing) under the heavier recoil of the 3" loads. Make sure you are solid behind the gun and have a strong magazine spring and your problem should go away.

    William

    http://www.OR3GUN.com
    meanstreak likes this.
  7. Yanger

    Yanger Copper BB

    Messages:
    7
    Hi William
    thanks for the input
    Would you recommend I try to push the cap retainer farther in or try stretching the spring to create more spring tension?
    meanstreak likes this.
  8. OR3GUN

    OR3GUN Sponsor Sponsor

    Messages:
    199
    meanstreak and Djcala like this.
  9. Yanger

    Yanger Copper BB

    Messages:
    7
    Spring ordered
    I'll report back once install it and see if it solve the problem

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