New AR tool

Discussion in 'AR 15 Forum' started by PRR1957, Jul 14, 2020.

  1. PRR1957

    PRR1957 Well-Known Member

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    Primary Arms sent this to me in my email today. With P A you get the price at check out. :confused: This is a new idea to tighten/loosen the barrel nut when assembling a barrel to an AR upper. Looks to me like a better idea for barrel attachment.

    1- Clamp the fixture in the jaws of a bench vice.
    2- Attach the upper receiver to the fixture, and pin the receiver to the fixture through the upper receivers pivot lug.
    3- Insert the barrel into the upper receiver trunnion indexing the barrel extension on the splines of the top extension of assembly fixture.
    4- Remove the bolt from a BCG, then insert the bolt carrier into the upper receiver sliding the bolt bore of the carrier onto the post on the top side of the fixture. This is to add additional support to the upper receiver.
    5- Tighten the barrel nut. 0CBA3ED3-A719-4093-BFD3-20C35292B7FD.jpeg
    The idea is with the barrel held in place by the barrel extension indexed on the fixture’s spline’s when tightening the barrel nut, the torque is divided between the barrel and upper receiver. This also eliminates the barrel from rotating when tightening the barrel nut and the possibly of distorting the upper receiver’s trunnion barrel index slot, and possibly shearing the barrel’s index pin.
     
    Last edited: Jul 14, 2020
  2. zant

    zant Well-Known Member

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    A great tool,been using for about a year.
     
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  3. PRR1957

    PRR1957 Well-Known Member

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    Good to hear.

    I only became aware of it yesterday.
     
  4. 68c15

    68c15 TFFWPP President Supporting Member

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    I bought a similar yet different tool from Brownells. I think they call it an action bar or something. It is a metal bar the same diameter as a bolt carrier and has very stout lugs to mate up with barrel extension. You clamp it down in a bench vise, but it has a 1/2" female square in the end if you want to use a torque wrench. I think it was about $35

    My concern for the one above is how well does it keep torque from being induced into the receiver? The thing I have puts absolutely no torque on the receiver
     
  5. PRR1957

    PRR1957 Well-Known Member

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    Well it’s a Magpul which all their stuff is molded fiber glass/polymer, so your guess is a good as mine.

    I worked for 6-1/2 years for an AR manufacture and assembled 1000’s of uppers using standard action block and never once did I twist a receiver or bugger the barrel extension index pin slot. We used molybdenum disulfide anti-cease grease for the barrel nut.

    The only tool I ever bought from Brownsmell was a Remington receiver action wrench. It’s inserted through the ejection port, so it only engages tge front of the receiver not the hole length so to twist the receiver. Those Remington 700, 40X, Model-7, and XP 100 barrels are 271 Loctite glued in.
     
    Last edited: Jul 26, 2020
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  6. howlnmad

    howlnmad Old Guy Doing Things Moderator Supporting Member

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    They look cool, must be worth buying :rolleyes:.
     
  7. ms6852

    ms6852 GUNZILLA Supporting Member

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    Wow, seems like it works better than my 2X4, and hammer and pliers.
     
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  8. JRK57

    JRK57 Well-Known Member

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    I have one of those (works great on AR-15's) and one of these. I had to get the one pictured in order to take apart and put together AR-10's. Just drop the upper receiver in side, and slide the pins in to lock in place then tighten in a good vice.

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