Should an AR's castle nut be staked?

Either staked or add just a small dab of blue loctite. My experience has been if you don't do one or the other it will loosen over time.

It you want it done properly to spec stake it. If you don't care and there's not a chance of needing that particular gun in a sustained fire fight your fine.

I have one now 10+ years old and the castle nut is not staked. In fact it also wears a commercial receiver extension and neither has failed or loosened.

If it’s my opinion to give, yes for a rifle, no for a Pistol that you intend to convert back and forth. For that instance, if you need to switch extensions, then LocTite. If that isn’t in the mix there are zero good reasons not to stake it, just make sure everything is square before grabbing the punch.

I tried the loctite idea on my first build. Diesel mechanic background, but won't rule out user error. However, my extension was free-spinning after 50 shots. Now, they all get staked. Had to pull a staked extension last week, proved to be no problem. Just bumped the dimple with a punch, and wrenched the nut through what was left.

I've never staked one, and haven't had an issue. I'm not building a gun to fight with tho. If I were id be using all the tips and tricks I could to make it as reliable as possible.

If it's going to be semi-permanent, I'd stake it. Loc Tite works well too.

I have lots of ARs with lots of rounds through them and haven't staked a single castle nut. I've used Loctite on a few in the past but didn't bother with that for the two Spikes MG lowers that I built. They have thousands of rounds fired on full-auto with 5.56 and 300 BLK uppers without staking or Loctite and no issues either. My take is not to do anything just because. Unless you're heading out the door into a combat zone why not let your AR tell you what it needs. I can see why the military needs a one-size fits all KISS approach but we don't.

Torque to spec, then stake it.

I've had a /staked/ one loosen when I had to mortar a stoppage clear. Rotated the receiver extension 30°.

Loctite ones? Seen a lot loosen just standing there shooting. Annoying delays even just on range days.

I’ve staked all of my collapsible ARs and I have never had one loosen...and all of my offices’ full auto M4s are factory-staked, so I don’t ever expect to have a staked castle nut loosen. Anything could happen, but I don’t know how one could loosen if it’s done right.

You may have perfect luck without the nut being staked, so the choice is alwaysyours .

Stay safe.

shoobe01 said:

I've had a /staked/ one loosen when I had to mortar a stoppage clear. Rotated the receiver extension 30°.

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Not sure how that’s possible with the receiver end plate limiting rotation to whatever slop the extension channel permits. A few degrees maybe, but you’d need to spin the castle nut several full rotations for 30.

Skylerbone said:

I have one now 10+ years old and the castle nut is not staked. In fact it also wears a commercial receiver extension and neither has failed or loosened.

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I bought an olympic as soon as the awb sunset. (Don't judge, it's not like there were many options back then) Not only is it not staked, its castle nut is backward. I carried and shot it for years and never had an issue. All the ones I use now are properly built though. But for a range toy. Idk

I never staked any of my 3 gun rifles, nor most of my coyote hunting rifles. My hunting rifles have been through hundreds of miles of rough treatment (used to sell a hundred to two hundred coyotes each year before my son was born), and my 3 gun rifles received worse, with far greater round count.

I have had a lot of rifles come to me to be staked, but I have only had my own come loose ONE time. Middle of a coyote hunt and I noticed it was loose. Guess what I did? Tightened it back by hand, torqued it when I got home the next week, and it’s been tight ever since.

A tiny dent in a non-critical component shouldn’t be such a high priority for the mil-spec mafia goons.

I've never staked one and probably never will, but if you want the extra security by all means stake away. All my stuff usually gets taken apart sooner than later so I avoid things that make it more difficult to take apart.

I've built several dozen ar's and only staked one castle nut. The dang thing actually broke loose after 2k rounds. Only one that ever has. I like to tinker, so a lower may get torn down every 1000-1500 rounds anyway, so torqued and a drop of loctite always works for me.

I have built 3 ARs and was told by a gun dealer while built guns for himself and others for competitions to use loctite blue on my first build. That’s all I used on the other two and will use on my latest assembly. I haven’t had one come loose but my guns are fun guns, not for competition.

I did have the castle nut loosen on my first build because of the curse of the internet. I read (on another forum after a search) the torque should be 40 in/lbs. Which I thought was stupid but it popped up in a couple of places. So, I torqued it to 40 in/lbs....Duh!
The logic was that people were breaking things at 40 ft/lbs so the number “40 must be in inch-pounds”.

Something people fail to do when doing their torque with an Armorer’s Wrench is calculate the added torque by using a torque wrench and the armorers wrench together you are essentially elongating the torque wrench therefore increasing the torque on the nut.

If you have a 16” torque wrench and the armorer’s wrench adds 2” to the length the setting on the wrench to achieve 40 ft/lbs would be 35.6. If 3” is added the setting would be 33.7. There are online torque extension calculators that can help with this.

Just thought I would throw that out there.

Just stake it like it is supposed to be, then you will never need to worry about it.

Stake it or don't, it's totally up to you.
If you don't and it works loose, you can always retighten it and stake it then.
It's your gun, do what you want.

I’ve heard a lot of guys say they never staked theirs and never had an issue but I’ve heard just as many say theirs did come loose, sometimes in as few as 50 rounds, sometimes it took a thousand.

I’ve never heard of a stacked castle nut come loose until shoobe01 mentioned it in this thread, and even that sounds a bit suspect to me.

Personally I picked up a center punch and stake, its easy to do any not that hard to remove if you need to. If you think you’ll need to swap out receiver extensions a lot use some blue Loctite.

I find the comments about “its not that hard to hand tighten if it does come loose” comical. While what they say is true, the AR platform seems to be the only firearm in existence where folks are OK with failures, like it’s to be expected.

Other AR bros will judge me, but on my rifles, I use a tiny dab of red loctite on the castle nut threads. It will never loosen and if I want to remove the tube, a quick heating with a torch and its easily disassembled. I've seen so many buffer tubes come loose from either lack of staking or no staking. For me, Loctite is just easier and effective.

I have never staked one.
Max torque spec & blue loc-tite.
Never had a problem with my 8 builds.

Sorry, no photos. And I didn't do that one, factory lower but it was machine staked, squared off dents. I was not happy with the look of the threads afterwards, so I tossed the receiver extension, endplate, and castle nut, did it all again, and used a center punch to stake the hell out of it.

I did have a weird situation. It was so muddy I couldn't find a bit of ground that worked, so whacked it on a log used as a barrier, and it fell into the crotch instead, so the butt was sorta forced to an angle as I brought it down. Call it all my fault Just using it as an extreme example, that you better do it right because even a really hard match day can stress the system. I did twist it by hand back, and ran the rest of the day with it hand tightened.


I have heard secondhand stories of 3-4 similar failures of properly assembled guns in the US Mil and one name brand police one, that got fallen on, dropped, etc. and loosened/rotated a bit. But not to stoppages.

OTOH, seen (myself) unstaked systems loosen so much the rcvr extension moves under load, and the buffer binds on recoil and the gun stops.


Also: do get good quality parts. Cheap castle nuts totally don't work as well.


Also also: I have a vague recollection of someone (e.g. LMT?) who doesn't stake, insists that proper torque is enough, but has good parts, good process, and tools to torque it right. Anyone else heard anything like that?

Staked one. Never loosened. Loctite blue....did not loosen and was a pita to take off later
Have had others.....nothing done but torqued.....did not loosen. Didnt buy top end parts....didnt buy cheapest either. My AR stuff has been boringly good/uneventful.

Blue loctite. Stake. Green loctite. Never had a problem.

My AR experience is very limited. But my tool and hardware experience is a bit better. A castle nut is designed to be staked or pinned. Hence the "castle-like" appearance. Those grooves weren't cut into a nut for the purpose of a specialty wrench. Maybe in the AR's case they used it for that reason? To be round yet removable? I don't know much about the AR designed or why the castle nut was chosen, but it's original function was to be staked.