Do all AR15 castle nuts have the same width of about 3/8"? I need a shorter castle nut; about 5/16" or 1/4". I have an old Knight’s QD sling receiver plate on my AR. It has the old style nut with the holes along the middle of the side of the nut and does not have the castellated cuts of the newer nuts. If I put the castellated nut on the buffer tube the adjustable stock will not catch the last position closest to the receiver. That is why I could use the shorter nut. I could just shorten the stock face that hits the nut, but I would rather not do that.
I’ve seen a post about the same problem, the thread recommended a bushmaster nut 5310-917-1153, which at the time (2010) was not castellated.
Here it is…
If you try the grind the side of the nut facing the endplate you will likely end up with an uneven edge that is not truely perpendicular to the RE, so when you crank it down it will try to force the RE offcenter.
Seems to me that the smarter course of action is to get a different sling attachment if it’s going to require crazy mods. Unless I am missing something.
I would not want to try grinding the nut. The best suggestion was to try backing the buffer tube out one turn nut I’m not sure I can get the non-castellated nut loose.
The Knight’s QD adapter runs about $85 to $90 new. Mine was installed in 2005 and has not given me any problems. It’s tight and I may have a problem removing it. I’m not sure the Tapco wrench I have is sturdy enough to remove the nut without breaking. I was just thinking about putting the castellated nut in place of the non-castellated nut that comes with the adapter so I could stake the nut to the adapter. It’s beginning to look like I’ll just leave it alone as it may just be too much trouble to replace something I’m not having any problem with.
I thought that an easy fix would be to just replace the nut with a castellated nut but the difference in size made for more problems.
A minute on a surface grinder will have it thinner and still keep it square.
The trick is finding someone with a surface grinder and the time to spare. As at work, or the gun club, local gunsmiths. someone has the machine, and would be willing to do it for a six-pack or pizza, or whatever.
I just noticed that Knights armament still sells the same part, won’t they sell a replacement nut?
I like the old style nuts, smoother feeling/looking and the wrench won’t slip off so easily when you are assembling on your lap like a caveman…
It seems like the old style would be easier to manufacture… I wonder why they changed… Just to add stake pockets?
The QD sling plate they sell now still has the same nut as the one I got in 2005. It’s a plain nut with the holes in the middle of the nut side (old style) and no staking cuts. If I can get the nut off I have two simple choices.
First, just cut a few staking cuts on the edge of the old style nut. Second, remove the old style nut and use a new style (castellated) nut and just take off the small amount from the face of the stock. I need to make the decision of if I’ll even remove the nut that is on it now. It’s tight and has not given me any problems. This thread may be a solution in search of a problem.
I’d leave it alone. IINM, KAC uses some type of thread-locker in lieu of staking. It hasnt moved since you got it and i doubt it will anytime soon. If it backs out then i’d take it apart, but unless it does, i see no reason to touch it. And if it does, your easiest solution is to cut a notch on your existing nut to accommodate staking. I’ve done it before and it’s incredibly easy.
I ordered a so called mil spec castle not from Palmetto State which didn’t have the staking notches and is just a little thinner than the actual mil spec ones I have. See if that works.