Quick Tip: The Right Way To Stake an AR-15 Castle Nut

Forget what you just read on Reddit and Facebook. There are plenty of wrong ways to stake an AR-15's castle nut. Then there's Caleb's Way, which he's going to demonstrate for us today. The castle nut threads onto the receiver extension (aka buffer tube) and locks the extension to the receiver. It's called a "castle nut" because of the evenly spaced wrench notches that make it look like the top of a medieval castle's tower. You stake the castle nut to the receiver endplate to prevent it from backing out, which in turn prevents the receiver extension from working loose.

Caleb demonstrates with a Geissele buffer tube, Bravo Company endplate, and a Forward Controls Design Castle Nut FCD. You'll need a bench vise, lower receiver vise block, cross-peen hammer, and a center punch - pointed tip or square tip is fine. Do not use a woodworker's countersink punch! Before he begins, Caleb shows us an example of how NOT to stake the castle nut: too shallow, with mere surface damage to the nut and endplate. You've gotta move some metal to do a proper staking job!

There are three small, shallow notches on the side of the castle nut that faces the rear of the receiver. Position the punch with its tip covering about half the depth of the endplate directly opposite a notch. Hold the punch so it stands straight out from the side of the endplate - don't angle it. Lightly tap it several times with the hammer to start making an indent in the endplate. Once you've made a nice indent to keep the tip of the punch from slipping, you can apply harder hammer strikes, but DO NOT whale on it!

When you're done, you should have a neat, circular dimple in the endplate, with a good bit of metal smooshed (technical term) into the notch in the castle nut. For an extra-secure installation, stake one of the other two notches in the castle nut. (You don't have to do all three.) That castle nut is NOT coming loose without your help!

Is staking really necessary? Find out in our earlier video "Smyth Busters: Does an AR-15 Castle Nut Have To Be Staked?"

Get the details on FCD's upgraded castle nut: "Product Spotlight: Forward Controls CNF Castle Nut"

[CalebSavant]

LocTite has destroyed more receiver extensions than staking. Change my mind....

[C_oprator]

Punch starter from harbor freight. No more “missed-stakes” aka mistskes haha I’m here all week folks

[SoloRenegade]

The best instructional content never makes assumptions about the audience's level of knowledge/understanding, and explains each item, defines all terms, doesn't skip steps or take bits of knowledge along the way for granted.

Videos like this are a great help to people and much needed to ensure people are getting the correct reference material.

[aaronskuse]

All this talk of Stake, but not once did I see A1 sauce. What a bunch of culinary savages.

[GickelsGaming]

Legend says that Caleb is still staking his castle nut

[jeffjacobs]

SAFETY GLASSES would be highly recommended! 30+ years as a Tool & Die Maker and I can assure you the flying debris in the eyes comes mostly from grinding and pieces coming off of a center punch.

[johnjohnalmand]

Been running an un-staked un-torqued buffer tube for as long as I can remember. I'm glad I found this video 😂. It doesn't take much movement at all to lose that spring and pin for the take down pin retention. If there's even a 1/16 gap ive had that spring fly out.

[Solly-owod]

About 3 to 4 shots with an automatic punch does the trick for me. Thanks Caleb.

[survivetheattack]

Good job! I do two stakes, as per mil-spec. The reason my fellow builders commenting here haven't had an unstaked castle nut back out on them "ever" is because those rifles have never been in the hands of an infantryman for a 12mo combat tour. Range and home defense guns don't need staking. Militia, military and law enforcement rifles need to be staked. Only time I've ever removed a buffer tube is to install one folding stock adaptor, and I was able to crank the staked castle nut off, no problem (replacing it with a new one, so I could re-stake.) 👊🏼🇺🇲👊🏼

[JLR]

Ive assembled hundreds of lowers and I use a center punch. It works well and you dont have to worry about hitting yourself with the hammer! 😅

[calvins]

Bought the exact tool you guys said to buy, did exactly what you said and it ended up cracking my end plate. Magpul endplate. Edit: It was because I started the punch process too close to the middle of the end plate I would definitely do a closer to 1/3 to a 1/4 from the side, worked night and day better for me and got a perfect stake. super easy.

[IRISHERETIC]

These are guys that keep me from going to ranges. "There's only my way of doing things or you'll get made fun of".

[johnnydhillon]

I'm glad to see you showing people the right way to do it, so many of my friends didn't even know that it needed to be done and the nut came loose at the range! I always carry tools with me just in case of this reason

[michaelshanahan]

I’ve been watching Brownells videos for years, always really good and this kid keeps getting better.

[Gniverse]

Spring loaded center punches work even better. Don't need a vise, can do it right on the workbench.

[kauboy]

For recent "reasons", I had to do an extension swap on my AR pistol, which I had staked in exactly this fashion. A good armorer's tool and some leverage will still undo the work, so don't worry about this making anything too permanent. Staking the castle nut is always advised.
That said, I suspect future court rulings to negate recent events, and I chose to not re-stake the nut upon reinstallation in anticipation of doing this work again sometime soon. If/when a final install is made, it will be staked again exactly as Caleb shows here, as this is the only good method I've seen.

[Fister_of_Muppets]

In my experience, a random "MILSPEC" LPK usually has a butt-plate that is easily workable with a good angled punch. However, I swapped in one of those Magpul QD butt-plates, and that was considerably harder steel to move. Using a good quality hard punch is key. If you don't have one, get one.

[eliinthewolverinestate]

I stalked mine twice. After watching how little it took to break loose a stake even after being properly staked. I used one of my smaller masons chisels and hammer. The many coats of paint help hold mine too. lol.

[garyh]

My first build I used a Primary Weapons System ratcheting castle nut. No staking needed. My second build, which I just completed, I used the standard castle nut. I have not staked it yet, but after watching the video I think I will go back and do it.

[JerrBearTactical]

I use a Starrett Steel Automatic Center Punch on every build I've ever done. It does a much better job moving the metal IMO and have been complimented by many gunsmiths and armors for having perfectly staked castle nuts. Mine look just as good as yours😉👊👍🇺🇸