Home CMMG Smyth Busters: Does an AR-15 Castle Nut Have To Be Staked?

Smyth Busters: Does an AR-15 Castle Nut Have To Be Staked?

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To stake or not to stake? No, that isn’t the title of an episode of Buffy the Vampire Slayer! Instead, Brownells Gun Techs Steve and Caleb tackle a long-standing debate among AR-15 folks: Should you stake the castle nut to the endplate on the receiver extension tube? Some folks say you should always stake it, while others say, “Nah, never.” Caleb is in the “stake it, stake it good” camp – and he explains the practical experience that got him there. If an AR-15 is used a lot, the castle nut WILL work loose. So unless the gun is a wall-hanger or a range fun gun, you should go ahead and stake that castle nut to the endplate – especially on law enforcement, military, and competition AR-15s and M16s. However, if you’re like Steve and tinker a lot with your AR, swapping stocks and the like, there is an alternative to breaking the stake every time you remove the receiver extension (aka, “buffer tube”). The Primary Weapon Systems (PWS) Ratchet Lock Castle Nut & End Plate use a pin-and-detent system that keeps the castle nut tight, yet lets you easily remove it when you need to. So among serious AR-15 shooters, not staking is the Myth – and it’s busted!

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44 COMMENTS

  1. I wonder how many people had them come loose after using a proper torque wrench. The most common cause of fasteners coming loose in any machine is failure to properly torque them to begin with.

  2. I had a new colt lower (factory) and it didn't come staked… say what you will about colt but it's a rare miss in my opinion. It came loose the first time I shot it and I noticed it while cleaning. Bought a PWS buffer and system and I've never had a problem since.

  3. My friend just built an AR and he literally only hand tightened it I mean without a castle nut wrench we shot 80 rd and it didn’t loosen at all but yeah I still do agree with your outcome would be terrible to be a cop in a shoot out then all of a sudden your castle nut goes loose

  4. I think I am going to buy that ratcheting castle nut. Pretty cool. It has a QD on it also. Little salty for a nut, but who doesn’t need a good nut?!

  5. I do not stake mine either bc I am always switching stuff around and not using the weapons everyday. However, I have made it part of my cleaning process to make sure the castle nut is tight. I clean every time the gun is shot w no exceptions, so I am not too worried about the castle nut coming loose with my limited use of the weapons. For military and LEO's though, I would stake it.

  6. Great content guys. For me it depends on the gun. If the build is finished & nothing is going to be changed I stake it. If there’s a chance I’ll be making changes I’ve found loctite & marking it with a paint pen works well. If I see it start to drift I’ll tune it back up & go.

  7. I stake mine, except for my Maxim brace which doesn't allow you to stake it & I've had that one back out on me. Ive also got one PWS ratcheting system, have yet to try it out (haven't fired the gun that has it yet since I just built it).

  8. My thoughts are if you are using your rifle as a civilian for home defense and range use, not staking is completely adequate. I shoot my ars regularly and havent had an issue. We are not commandos we are patriots. But im not knocking it, as better safe than sorry.

  9. Only watched this cuz wondering "wtf is a castle nut?"..😂😂
    Did not take long to figure it out and find that I've worked with castle nuts many times before thru the years.. English just being my third language and therefore not familiar with the english name of the part.. Oh well – every day you learn something new.😁

  10. Oh please how about checking that everything is tight first before handling on the range? No need to stake its a perfect way to trash a lock ring and buffer tube shoe goo on the treads or blue loctite is the way to go!

  11. +1000 on the locktite. You do not want your buffer tube coming loose, it could cause a misfire, and you definitely don't want that. I've build 100s of ARs and I put locktite on everyone of my customer's castle nut. Not one complaint yet!

  12. I don’t stake the castle nut and I don’t stake the gas key screws either. Waste of time and pointless if you tighten it up right and use blue or red loctite it will not come loose. But everyone in the comments is using their AR-15 everyday in all aspects of their life’ so they need it staked or they will definitely die🙄🙄🙄

  13. They where loose but guess what ill bet they still work even loose i know mine does i have it loose because i dont have the takedown pin detents installed yet

  14. Well, one has to understand threads and fasteners first. The threads stretch a little bit. And metal has memory, meaning it tries to go back where it was. This creates the clamping force. Now, that will stay in place under only so much force. A firearm going off transmits far more force than the torque needed to break the nut loose. So his comment about how much it is used is probably right.

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