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single action bar vs double action bar

Discussion in 'Mossberg 500 Pump Action' started by Mustachio, Sep 10, 2020.

  1. Mustachio

    Mustachio .410

    Messages:
    31
    I have an older model 500 in 20 G. Can the single action bar be retrofit to a double action bar? Would it require a new bolt carrier that has the other side notched? Can I get a replacement single bar, any where?
    meanstreak likes this.
  2. Bobster

    Bobster .30-06 Supporter

    Messages:
    2,145
    I'm pretty sure the bolt is different. If there is no excessive wear to the bar or bolt, I wouldn't worry about it but I would probably start acquiring the necessary 2-bar parts to convert down the road...

    PS: does the receiver have the 2nd slot in it?
    meanstreak and old mossy like this.
  3. old mossy

    old mossy Global Moderator Staff Member Global Moderator Moderator

    Messages:
    12,868
    We had a member trying to do the same thing,convert to duel bars. This was awhile back and I don't remember if they ever got it done. I do know some of the early receivers only have one hole for the bar. Not sure what needs to be done to innards.
    cut out not.jpg
    cut out.jpg
    meanstreak likes this.
  4. hombre243

    hombre243 .30-06 Elite Member

    Messages:
    1,085
    There is a channel on the inside wall for the action bar.
    meanstreak likes this.
  5. old mossy

    old mossy Global Moderator Staff Member Global Moderator Moderator

    Messages:
    12,868
    Also with the new slide action you will need the new style mag tube.
    This is a pic of old style ,,,,,,
    old type mag tube.jpg
    meanstreak likes this.
  6. Mustachio

    Mustachio .410

    Messages:
    31
    I just got off the phone with Mossberg-the mother ship. they no longer make the single action arm assembly. However, the dual action arm assembly is generally in stock for the 20 gauge. they had none in stock but said to call back in 3 weeks. I would have to take one arm off, he suggested a gunsmith to do the work. Is this something I can do? I am pretty skilled in a lot of areas-my wife says that I can fix most anything and so far she has been right. He also said that right now all parts are going into building shotguns and none are for parts replacement since the market is so hectic.

    Alert: I just found a single arm action assembly in 7 3/4". Is this the size I need? or do I need the 6 3/4" tube? thanks for all the information on this...it is extremely helpful.
    mustachio
    Last edited: Sep 11, 2020
    meanstreak likes this.

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