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Pivot pin is really stiff

Discussion in 'Black Rifle Forum' started by ustate, Jan 3, 2012.

  1. ustate

    ustate NRA Member

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    I'm in the middle of my first build and I'm working on the lower. Its a RRA receiver and CMMG lower parts kit, I haven't really tried/worried about the front pivot pin much yet but holy cow is that thing stiff and not wanting to budge. Is that normal? I assume once you start utilizing it the pin will start moving more easily but is there any trick to get it started?
     
    Last edited: Jan 3, 2012
  2. faawrenchbndr

    faawrenchbndr CLM

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    Oil it a bit and cycle it
     

  3. zhix

    zhix

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    Rock River receivers are tight. I had one that would not fit with the upper I wanted to use with it; I guess the oil eventually soaked in because I tried it again some time later and they were still tight but fit together.
     
  4. Cole125

    Cole125 Silver Member

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    Put a little oil on it and it will break in over time. I have been happy with the quality of parts in my CMMG lower parts kit I used on my first build.
     
  5. Three-Five-Seven

    Three-Five-Seven Señor Mombo Millennium Member

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    No, not normal.

    Visually inspect how well the upper and lower pin opening line up.

    Does the pin go into each half of the gun without resistance? In other words, are the holes the proper size or/and is the pin .250 ?

    While the take down pin can be tough to engage the first time, the pivot pin should have little resistance.

    You are assembling in the proper order, right?
     
  6. ustate

    ustate NRA Member

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    Yeah, I'm putting it together in the correct order. The pivot pin went in nice and smooth, now it doesn't want to open at all. I'm oiling it and playing with it hoping that it will eventually open up. I'm not able to get my upper until next month so I've got time to play with it and hopefully get it going.
     
  7. Mayhem like Me

    Mayhem like Me Semper Paratus

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    My guess is you used the wrong detent OR the detent has a square end instead of the rounded end digging into the pivot pin, some kits have both ends rounded some do not. The rounded end should be placed toward the pin, the squared or flat end toward the receiver.
     
  8. ustate

    ustate NRA Member

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    Is there a way to safely remove the pivot pin even if the detent is in backwards to check? I know it is the correct detent but would like to check if it needs to be turned around.
     
    Last edited: Jan 4, 2012
  9. Mayhem like Me

    Mayhem like Me Semper Paratus

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    Yes if you have good eyesight and a small pick pull the pin out all the way, you will see where the detent is engaging the pin in the goove that faces the receiver.
    Use the tip of your pick to hold that in and slowly wiggle the pin free and cup your hand over the pin detent assembly.
    As you slide the pin out the detent will come out under the spring pressure, best to do this over a clean floor or a white sheet sop you can reclaim the pieces.
    Assembly is tricky I use a slave pin I can push through but it can be done with a steay hand as the detent has a ledge that will allow you to hold it in with a pick as you replace the pin.
     
  10. ustate

    ustate NRA Member

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    Thanks, I'll give it a try tonight when I get home.