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Discussion in 'AR15' started by Glenn654, Jan 5, 2012.
Is there a torque specification for the nut on an AR's buffer tube?
I just leaned on mine till it felt snug and happy
looks like its supposed to be 40+- 2 foot pounds, plus properly staked
EDIT: we are talking about the locking nut on a carbine buffer tube correct?
from Tech manual
There is no set torque specification.
Install the castle nut and hand tighten it down. Then use an appropriate castle nut wrench to further tighten it by hand. You should be using either a padded vice or if you don't have a vice by laying the lower receiver on it's LEFT side with the buffer tube off of the end of the table. Have a buddy hold the receiver down so that the pistol grip acts as a stop while you rotate the castle nut with the wrench to further tighten. This will not damage your receiver.
You only need to use the leverage of your hands and the wrench itself.
Once that is done the proper way to fix your castle nut is to properly stake it not use lock tite or thread locker.
If you look at the barrel end of your castle nut you will see small divots cut into the end of it. Those are the staking points where you take your punch and stake it.
The only time you should use thread locker on it is if you have something like an aftermarket single point sling or adapter receiver end plate that is made out of harder steel than the standard one and it is too hard to stake with the castle nut.
What I posted above is what I do, and is taken straight out of one my AR15 Gunsmithing guide books which I happen to have here on my computer desk.
Gunsmithing the AR15 by Patrick Sweeney
Thanks for the info Pothole and the link the the Tech Manual...it will be very helpful.
And to TACAV...The description of how to do the installation was also very helpful...didn't know about having to stake castle nut.
Is there a source which gives step by step instructions to follow for a build.
It's my first one for a friend who doesn't have the required patience when dealing with all the little springs etc. I know I'll enjoy the build but don't know some of the finer points.
This is a good guide for AR assembly with clear pics etc.
Amazon.com: The AR-15 Complete Assembly Guide (AR-15 Guide Vol 2) (9781888722123): Walt Kuleck: Books
That's "Inch Pounds" not Foot Pounds!
There is a big difference, read that upload on that manual page again.
If you try and use a wrench calibrated in foot pounds you will probably mangle things up.
Torque Wrenchs in inch pounds are out there.
I just tighten it with my AR15 tool til it feels secure. Never had one loosen up on me.