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Stumped....shell capacity?

Discussion in 'Mossberg 500 Pump Action' started by flintknapper, Jan 8, 2020.

  1. flintknapper

    flintknapper .22LR

    Messages:
    27
    Kind of strange.

    I have two identical shotguns (M500A Flex Security). Both have about the same round count on them (less than 500 rounds).

    One of them will hold 6 shells in the magazine tube, the other only 5. They have both been like this since new. The Magazines measure exactly the same length. The shells are all the same length (just different brands).

    When I compare the magazine springs...they both appear to be the same diameter and coil count, though the spring on the shotgun that only accepts 5 rounds is actually about 3/4" shorter.

    I swapped the spring from shotgun (B) that holds 6 rounds into shotgun (A) that only holds 5 rounds and it made no difference.

    Question: What might be the reason for this disparity? Both shotguns have the same follower (Factory swapped out for NDZ).

    Shell Capacity_a.jpg
    Shell Capacity_c.jpg
  2. John A.

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

    Messages:
    14,674
    Looks like 1 spring is a little longer. I also cannot see the inside of the follower to see if it allows one spring to protrude farther internally or not. I also cannot tell about the white shells. Are they 3 inch instead of the 2 3/4" that are on the bottom? If they're 3 inch, that's where your discrepancy is at.
    fellmann likes this.
  3. fellmann

    fellmann Esoteric Supporter Premier Member

    Messages:
    617
    If you use the same length of shells.. try the longer spring with its follower in the "lower capacity" tube.. If that fixes it - buy another same type of spring :)
  4. Pawpaw

    Pawpaw .30-06 Supporter

    Messages:
    1,781
    You said, "The shells are all the same length (just different brands)."

    Did you measure them, or are you just going by the fact that both boxes say they're 2 3/4 inch shells?

    There is a lot of variation in the loaded length of "2 3/4 inch" shotgun shells. My 930 SPX is supposed to hold 7+1, but I could never get more that 6 Federal 00 buck shells in it. They are on the longer side for 2 3/4" shells.

    Try swapping the shells around between the two guns. You may find that shell length really is the issue.
    John A. likes this.
  5. Chris_K

    Chris_K .22LR

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    26
    I just noticed this shell length variation issue, after shotgunning for years many years back. My new to me 500A 20" barrel with 8+1 capacity doesn't seem to wanna hold more than 7+1 with Federal bird or buck. It does look like the shotgun on the right has a shorter tube, but you measured it, so it must be optical illusion.

    Blows my mind that not all 2 3/4 shells are exactly 2 3/4... :D
  6. old mossy

    old mossy Global Moderator Staff Member Global Moderator Moderator

    Messages:
    12,709
  7. old mossy

    old mossy Global Moderator Staff Member Global Moderator Moderator

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    12,709
    Here's one pic,,,,
    shell size.jpg
  8. flintknapper

    flintknapper .22LR

    Messages:
    27
    2-3/4" is the 'after fired' length, the loaded length is always shorter than the shell designation.
    Chris_K likes this.
  9. flintknapper

    flintknapper .22LR

    Messages:
    27
    I measured two of them and they were 2-1/4" (loaded length)just like the Hornady Critical Denfense I keep in one of them....BUT...I should have measures ALL of them because 3 of the 5 measured 2-3/8" (loaded length). So the stacked tolerance in aggregate was 3/8" longer and that was the difference. Good call.

    Should have figured that out by myself. But I'm old now...so that is my excuse. :idk:
  10. flintknapper

    flintknapper .22LR

    Messages:
    27
    ^^^^

    No, not 3"..though the angle makes them look longer than they are. Looking at them...I remember now what I did. My Daughter's shotgun (the one on top in the second photo) has two different manufacturers shells.

    I had Her's loaded with a (#1 buck Sellier&Bellot) in the chamber followed by two more in the magazine (first three shots #1 buck) followed by 3 (Fiocchi #00 buck). The S&B shells are 1/8" longer (loaded length).

    So...after cleaning her shotgun....I forgot about that arrangement and shucked a 00 buck in the chamber and then put all three S&B's in the magazine along with the Fiocchi's. Turns out I can get 6 of any shell that measures 2-1/4" into the magazine...just like in my shotgun. Should have paid attention to that. Simple solution, but I feel kinda foolish about it now.

    Anyway, good call guys. Appreciate it.

    Flint.
    Chris_K likes this.
  11. John A.

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

    Messages:
    14,674
    Don't feel bad about it. Nothing to be ashamed of at all.
    Chris_K likes this.
  12. Chris_K

    Chris_K .22LR

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    26
    As much as I've learned in my journey down the guns rabbit hole, there's always more to learn, like I did on this thread. Humility is critical in life. :) Always be willing to learn, if someone is willing to take their time and teach you with it.
    Bobster and John A. like this.
  13. flintknapper

    flintknapper .22LR

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    27
    ^^^^
    Could not agree more.

    I just turned 65 years of age...but am ever the student.
    John A. and Chris_K like this.
  14. Pawpaw

    Pawpaw .30-06 Supporter

    Messages:
    1,781
    You're 65? Now I know who's been putting those scuff marks on my boot heels! :laugh:

    FWIW, it was my 930 that taught me about shell length variation. With the factory-supplied Choate mag tube extension, I could load 7 of whatever birdshot shells I had on hand at the time, but only 6 of the Federal 00. I was determined to use Federal FliteControl buckshot, so I spent a lot of money replacing the extension to get it to hold 7.
  15. flintknapper

    flintknapper .22LR

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    27
    Did some patterning with various shotshells today at distances from 10yds. to 40yds. That was kind of eye opening in a couple of circumstances.

    The shotguns are designed and intended for relatively short range defensive use (18.5" barrels and Cylinder chokes), but shotshells/loads varied widely.

    I shot some #1 buck (several manufacturers), some 00 buck (2-3/4" and 3" different manufacturers as well), some 3" Magnum #4 and last (and MOST unpleasant) some Dixie Tri-Ball (brutal)!

    I've never been recoil sensitive...but by the 3 round of Dixie Tri-Ball....I'd had enough. Don't really need to have detached retinas or the fillings in my teeth shook loose.
    Chris_K likes this.
  16. Chris_K

    Chris_K .22LR

    Messages:
    26
    Just took my new to me 500 out and man I feel that. :)
    John A. likes this.

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