Lock Ring & Castle Nut (Rare, Hard to find)

(5 reviews) Write a Review
$9.95 - $24.95

Used to tighten the Carbine Buffer Tube to the Lower Receiver, the US Military has used two different versions.

 - Lock Ring- original Style, used on XM177's, early Carbines, etc. Long out of production so this is a difficult item to find. Needs the Lock Ring Wrench for tightening (Here)

 - Castle Nut- replaced the Lock Ring (above) and is still the current style. Typical for later model Colt Commando's and M4's. Many AR tools have a solution for tightening this castle nut.. there is a Castle Nut Wrench (Here)





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  • 5
    It's the Real Deal

    Posted by John W on 25th Mar 2021

    Perfect, exactly what I was looking for.

  • 5
    Receiver extension rare lock ring

    Posted by Glenn on 15th Oct 2020

    Dimensions are era correct. Other than the color being slightly darker, you can’t tell the difference between original.

  • 5
    perfect for replacement on a colt

    Posted by charles clendenning on 4th Oct 2020

    used this to replace the consistently walking locking ring on a Colt SMG (9mm, so hard recoil in the AR platform). it is functionally perfect and even has the color correct!

  • 5
    Retro build

    Posted by Jeffrey on 21st Apr 2020

    Perfect part for my Vietnam era colt build. This is the only site that has it in stock.

  • 5
    buffer tube nut

    Posted by Robert C.Christ on 29th Sep 2019

    a great part, so hard to find for a Retro build!