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Discussion Starter · #1 ·
I have 3 factory Colt AR's, all three lower/uppers are fastened by a slotted screw. Can someone please tell me the factory torque spec. ,or range . I'm assuming it's in single digit inch lbs., possibly low teens. Also, what is a tool less upgrade. I believe they are 90's production..... Could there possibly be two different diameters ? Thanks in advance - Ed
 

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Here's my 2002 model 6721 HBAR carbine, take a look at the small vent/ weep hole behind the pivot pin on the raised area of the lower receiver, if your lower have this it could be converted to the mil-spec tool-less push takedown pivot pin.

If you don't have this noted hole and you have the small 0.250 pivot hole you could send it to an AR shop like ADCO Firearms (OH) or Specialized Armament Warehouse (AZ), or other to have it drilled, there's a deep small detent spring hole that is behind the takedown pin head and the noted small vent/ weep hole shown on my pic.

You will have to remove the pivot screw by using either two screwdrivers or just a screwdriver on the left side, they have some kind of threadlocker but could be removed with more effort.

There are two sizes of Colt pivot pins, the older ones are 0.315" diameter from 1964 to 1990 models, then the smaller mil-spec size 0.250" DIA from about 1990 to current production.

See my picture, if it have a small hole behind the right side pivot pin, it could be converted to a mil-spec captured push pins, these mil-spec pivot pins are available from large online sources like Brownells, MidwayUSA, KNS Precision, Specialized Armament Warehouse, etc.

The standard mil-spec takedown pin are made up of the pivot pin, detent pin and detent spring, installing the detent pin on the lower receiver was a challenge, I lost the detent when I first tried it on my first lower build, I learned by using a clear plastic bag over the front of the lower receiver to capture flying detent pin.

There is also a tool for installing the detent pin and pivot pin that makes it easier, I also ended up getting one to speed up my lower assembly time.

If you have the large size 0.315" pivot pin you could still convert it to a push button pivot pin from KNS Precision (see link below).

I also converted my father's Colt 1993 model 6830 7.62X39mm caliber carbine because his lower receiver had the pivot pin detent holes but it came from the factory with pivot screw.


Magento Commerce


Magento Commerce


AR-15 Upper Receiver Comparison and FAQ
 

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Discussion Starter · #4 ·
Thanks guys - 1911, your profession and interests represent quality . And Wheel , I knew you were the MVP after my first couple days of reading ColtForum
 
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