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

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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 very difficult item to find. Needs the Lock Ring Tool for tightening (Here)


- Castle Nut- Replaced the model above and is still the current style. Typical for later model Commando's and M4's. Many AR tools have a solution for tightening this castle nut.. there is a special tool for this if you need (here)

  • 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!

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