Mossberg Shotgun dropping shells for mag!

Discussion in 'General Shotgun Discussion' started by redneck1676, Oct 9, 2014.

  1. redneck1676

    redneck1676 New Member

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    Good morning all. I've got a Mossberg 500 and 535 and I'm having a problem with live shells being ejected from the bottom magazine port. Here's the situation on either model gun with any brand or shot or slug type of ammo, I will load 1 shell in the chamber then 2 more into the magazine. When I fire the first shell, then cycle in the second shell, the third shell will fall out of the magazine port. This happens about 6 out of 10 times with either gun. Anybody ever heard of this happening? Thanks Jason
     
  2. John_Deer

    John_Deer New Member

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    There either the magazine tube is coming loose or the shell stop and interrupter are not functioning properly. Check for proper assembly, broken parts, function of the trigger group. Look for obvious and simple problems.

    If you cannot say this is why my gun is not working with certainty take it to a gunsmith. It is better to just pay a gunsmith for 1/2 hour of his time than to throw parts at a gun with no certainty your gun will be repaired.

    Youtube is full of videos on checking the assembly and trouble shooting Mossberg parts.
     
    Last edited: Oct 9, 2014

  3. Rex in OTZ

    Rex in OTZ Well-Known Member

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    Dealing with double feeds , late feeds, and no feeds of the shell/cartridge from the magazine of the Mossberg 500 and other shotguns is a matter of controling the shell/cartridge stop and the interruptor. (info below assumes a clean gun)

    On the Mossberg 500 series guns the stop is on the inside left panel of the receiver and the interruptor is on the right side internal panel. They are held in place by the trigger housing and are easily removed (or fall out) when the housing is removed from the receiver .

    The cartridge stop is actuated in and out by a small tab protruding upward near the front of the stop (just back from the front curve) as it interacts with the left slide action bar . (tappered ramps meet during the feed cycle and pull the stop to the left releasing the shell from the magazine. When the bolt is forward, the shell stop is allowed to be at rest and hold the shell head to prevent shells from coming out of the magazine tube.

    The cartridge interruptor is actuated up and down on it's pivot with its interaction with the bolt slide. The front of this interruptor moves downward during the feed cycle to prevent the second shell in the magazine from coming out . (double feeding). When the bolt is forward the head of the interuptor is held out of the path of the shell head in the magazine allowing it to push up against the shell stop where it is held in place. (read above)

    The most frequent adjustment needed in this sytem is with the cartridge stop. If not adjusted properly it will allow the shell head to pass out of the magazine at the incorrect time, or it will hold the shell into the magazine when it is suppose to release it into the action. Since there is some variation allowed in the diameter of the shell base in catridge manufacturing there are times that changing brands, or lots ,of shells can correct feed problems. A much better way however is to correctly adjust the stop so that it will reliably feed all brands having some tolerance built into the gun by adjustment.

    To adjust the shell stop you should first observe its range of movement during operation. You can use dummy rounds, feeding them with the gun held upside down to observe how the end of the stop mates with the base of the shell. With the bolt forward there should be sufficeint engagement to hold the shells into the magazine.(even when wiggled slightly by hand the shell head should not jump past the tip of the stop).

    If this is not the case, the front half of the stop can be adjusted (bent) to increase the engagement. Do this by removing the stop from the gun , and clamp the rear half in a vise, then bend the front in the direction of the curve in the front tip of the stop. Do not overadjust, it takes only a small amount to make a big difference. If overadjusted the ramp ingagement of the stop and its actuator ramp on the action slide bar will not mate properly. This can cause malfunctions and can damage the tips of the ramps.

    If the shell stop is holding the shell in the magazine with good engagement, but will not release them during the feed cycle, then you must adjust the tip of the stop by removing just enough material from it to give clearance for the shell head to pass while the stop is pulled out of the way. Making sure that you have proper engagement of the ramps to provide the full movement of the the stops tip out of the way is important before you remove material from the tip. Again, this doesn't generaly take a lot of adjustment so remove only a small amount of material at a time using a file or dremel tool.

    If you study the operation well before adjusting you should be able to tune this stop to the middle of it's proper travel and take away the possiblity of small variations in the diameter of the shells base causing a problem.

    With the shell stop working properly there is seldom a problem with the interruptor. The tip of the interuptor has a less critical range of motion and is controled well by the pivot method. What the interruptor does is swing into position during the feed cycle before the first shell clears the magazine. By being in a position in front of the magazine opening at this time it prevents the second shell from being released during the action cycle. If it does not hold the second round from coming out of the magazine the result is a double feed jam. If it does not allow the first shell in the magazine past it to rest onto the shell stop, you will have complete failure to feed out of the magazine. Adjustments can be made to the tip of this stop by bending it in the direction needed to prevent the problems mentioned - it's just that this is a seldom seen problem.*


    [ame]http://m.youtube.com/watch?v=qYcaZd2cDn4[/ame]
     
  4. windjammer69

    windjammer69 Member

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    Me too

    I HAD three different Mossberg 500 that did this from the first time that I shot them. Had two at the gun shop but they still did the same thing. So I gave up, I have not had this trouble with any other pump or auto (Remington, Winchester, Browning). This was a problem not only for me but EVERY ONE that I know that has owned Mossberg's. It seemed to be some kind of flaw in the design.
     
  5. kfox75

    kfox75 Well-Known Member Supporter

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    Never had it happen myself, but this is not the first time I have heard of it.

    Redneck, DICOR the shotgun, and inspect not just the parts, but also the channels that they seat in. Sounds to me like they may be dirty or over oiled. There is no way to get the shell stop and the interuptor in the wrong slots on a 500, as one has a post sticking of the side so it will only seat in the proper place. Check for worn or bent parts while you have the shotgun apart.

    best of luck with this.
     
  6. John_Deer

    John_Deer New Member

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    I put a lot of rounds through Mossberg pumps. When shells are coming out of the magazine something is broke. One thing about a Mossberg that throws a lot of shooters a curve is the magazine tube will come loose. Also Mossberg will ship guns with a loose magazine tube. When I got my 20ga the magazine tube was loose from the factory. Luckily my gunsmith loves Bojangles chicken. A piece of chicken and a biscuit is a suitable rental fee for his hand tools.
     
  7. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The most common cause of this in ANY tube fed shotgun is fouling. Specifically fouling between the shell stops and the inside of the receiver. Remove trigger group and shell stops. Clean shell stops and the recesses in the receiver. They must move in and out in a controled fashion to allow one, and only one round to feed from the tube.
     
  8. John_Deer

    John_Deer New Member

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    I do not see how one can manage to jam the shell stop or interrupter with debris. I have seen many people shoot hundreds of rounds of cheap, nasty, walmart grade ammo in all makes of shotguns. There shotgun never malfunctioned. A standard sporting clay course is 100 rounds.

    Disassemble a pump shotgun and spray it with CLP. Wait five minutes for CLP to emulsify. Then wipe out the receiver with a paper towel or an old towel. Make sure there is no debris in the receiver. I usually blow out the receiver after I wipe it down to be certain all debris and excess oil are gone. After that I put a spot of grease on the hammer and the tips of the shell stop and interrupter. My pump shotguns never give me any issues unless a part is actually broken. My pumps work so freely I can hold the gun by the fore-stock with one hand and work the action. Jerry Miculek released a video on care and shooting a Mossberg. His pumps function just as freely as my pumps. Massad Ayoob says the Mossberg 500 is the most dependable self defense weapon you can buy.

    Here is Jerry Miculek's video
    http://youtu.be/Z3m-WNk44hI
     
    Last edited: Oct 22, 2014
  9. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    I have seen this literally dozens of times. Our range guns were old Winchester 1200/1300's. They would get 500 rds a month with only daily bore swabbing. After 6 months or so they would do this. Detail clean, good to go for another 6 months. Many of these guns had thousands of rounds of birdshot, buckshot and slugs through them and a good cleaning was all that was needed 99% of the time
     
  10. redneck1676

    redneck1676 New Member

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    Thanks for all the responses, its great to know there are people out there that will help diagnose a problem. Haven't had time to get into the 500 or 535 yet, but soon as I have a result I will let you all know. Thanks
     
  11. windjammer69

    windjammer69 Member

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    Go to any gun club

    Go to any Gun Club that has Trap, Skeet, or Sporting Clays and tell me how many Mossberg you see.
    One time over thirty years ago a guy tried shooting a trap model Mossberg at a 5 bird shoot and he could not load a shell from the mag because it fell out on the ground when he tried. Last and only time I saw one.
    Since then I have not seen any (Mossberg's) on these types of ranges and that is because they are not reliable.
    And I have shot on ranges all over this country. Ohio, Pennsylvania, New York, Kentucky, Indiana, Tennessee, South Carolina, Florida, Texas, New Mexico, Arizona, Utah, Montana, & Washington State, just to name a few. By the way my fav Gun Club is the Holiday Gun Club in Slat Lake City.
    And it is not because they have not been clean, if anything I clean my guns too often.
    Would you want to depend on a gun like that for hunting or self defense?
     
    Last edited: Oct 23, 2014