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mmr tactical gas block

Discussion in 'Mossberg MMR Hunter And Tactical AR15' started by John Thompson, Jun 29, 2015.

  1. John Thompson

    John Thompson .22LR

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    How do you remove the stock gas block on the tactical rifle so that the hand guard can be swapped out for a lighter one. Mossberg tech. says that you can not, they have a special tool for doing that. I have seen to many of these guns on you tube with other than the factory hand guards on them. So are owners drilling these gas block out and then replacing it with a after market one. The quad rail on this gun is much to heavy and big. Thanks for any help.
  2. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

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    21,086
    Howdy @John Thompson .

    Can you post a photo of the gas block from both right/left sides? I don't have an MMR, but know my way around the AR platform and should be able to answer your question if I can see what type of gas block they use...
  3. John Thompson

    John Thompson .22LR

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    Hope this helps
  4. John Thompson

    John Thompson .22LR

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    Not sure how to post photos in this format
  5. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

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    21,086
    If you're not using an image hosting site you may have to resize the photos on your PC...
  6. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

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    21,086
    Either way, there are three major means to secure a gas block:

    1) Taper pins - This is the most common type which uses two tapered pins driven into the gas block from one side and into channels drilled through the underside of the barrel. These pins are often installed with a hydraulic press and while they can be difficult to remove, can be pushed out using a punch and mallet.

    2) Set screws - These gas blocks are held in place using one or more set screws that seat into dimples or depressions drilled into the bottom of the barrel.

    3) Clamp on - Pretty self explanatory here, but not used all that often

    I believe the MMR line uses taper pins, but just want to make sure before we try to give you any removal advice...
  7. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

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    21,086
    Looking at stock photos of the MMR Tactical it looks like a free float set-up, so you shouldn't have to remove the gas block to change the handguard...
  8. John Thompson

    John Thompson .22LR

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  9. John Thompson

    John Thompson .22LR

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    I am trying to replace the stock hand guard with a 9" UTG FREE FLOAT SUPER SLIM RAIL. This rail comes with it's own barrel nut and locking system, so the old barrel nut must be removed and it can not be removed with out removing the gas block.
  10. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

    Messages:
    21,086
    Ok, those photos helped.

    That gas block is secured using taper pins. With the muzzle facing away from you, the pins are driven in from the right side of the gas block (as circled in your photos)and can only be driven out from the left. The pins can be very difficult to remove but by using something solid to support the underside of the gas block and a proper punch & mallet, they usually come out after a little effort and a few four letter words. The key is to use a taper pin punch which is essentially a 3/32" nail punch. The concave tip allows the force of impact to distribute evenly over the taper pin without deforming the surface. A flat head punch could deform the pins and make them very difficult to remove...
  11. dieselmudder

    dieselmudder .30-06 Elite Member "Philanthropist"

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    2,108
    Penetrating oil, (wd-40, pb blaster, deep creep) will help. Give them a squirt then go do something else for awhile. Come back and try punching them out later.
    LAZY EYED SNIPER likes this.
  12. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

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    21,086
    We're still talkin 'bout guns right?
    FullAuto556 likes this.
  13. dieselmudder

    dieselmudder .30-06 Elite Member "Philanthropist"

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    Can't take you anywhere now can we...... Yes still talking about the taper pins, in the gas block. On the barrel
    John A. and LAZY EYED SNIPER like this.
  14. John Thompson

    John Thompson .22LR

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    Well you know what they say in the army, this is my gun and this is my weapon, one is for fighting and one is for fun. ANYWAY, back to the task at hand. When I punch out the tapered pins in the gas block will I be able to use the gas block and pins for the reinstall or will I need to purchase another low profile gas block. If I have to or want to replace the gas block how will I know what to get or are gas blocks a standard size and diameter. By the way thanks for your help with the pin removal. It's a good thing when those with knowledge are willing to share it with those who are trying to learn.
  15. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

    Messages:
    21,086
    Yes Sir.

    If all goes well with the pin removal you should be able to reuse everything, assuming the gas block fits under the new handguard. If for some reason the pins or even the gas block gets mucked up it's not the end of the world. Most aftermarket gas blocks that use taper pins are made to the same specs and replacement parts are relatively cheap.

    Glad to help.

    It's what we do here...
  16. John Thompson

    John Thompson .22LR

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    10
  17. LAZY EYED SNIPER

    LAZY EYED SNIPER Overwatch Staff Member Global Moderator Supporter "Philanthropist"

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    21,086
    Sorry, I should have sated in my earlier post that the direction described was with the rifle right side up.

    The direction indicated by your arrows is the direction in which the pins are installed. To remove them, you will need to push them out from the opposite direction of your arrows...
  18. K.T. Wolfie

    K.T. Wolfie .22LR

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    This is the ejector side of the gas block:
    [​IMG]

    This is the safety lever side of the gas block:
    [​IMG]

    I have attempted to remove the pins going both directions to no avail. My problem might be an improper punch, so I will get a different one and retry.
  19. John A.

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

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    14,287
    A taper pin is just that.

    There will be one side slightly fatter than the other.

    You drive them out by striking the skinny side.

    From lack of better explanation.

    Some taper pins can be a royal pain to get started moving, but usually once you do, they come out rather easily after.

    There was one occasion where I had to grind the gas block away from over the pins so I could remove them that way and thus it needed replaced afterward. But in all fairness, that upper had been subjected to pure hell.

    Like I said, most just need a few really good whacks to get started moving, then the rest is easy as falling off a log.
  20. K.T. Wolfie

    K.T. Wolfie .22LR

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    My original assumption was that they needed to be removed by striking them on the safety lever side of the block because the center of the pins had a slight point & the ejector side were flat. After a couple of healthy wacks with my brass hammer, the pins refused to budge. I decided to never assume anything and tried the ejector side, to no avail. I believe the issue might be my punch is a wee bit too big in diameter.

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