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Primary Weapons Systems Ratchet Lock Castle Nut & Endplate Set

Manufactured by Primary Weapon Systems
Manufactured by Primary Weapon Systems
5 Reviews

In Stock

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The PWS Enhanced Ratchet Lock Castle Nut and Endplate Set can be used with any Mil-Spec or commercial buffer tube set up for AR-15 or AR-308 rifles. It allows you to securely attach the buffer tube without staking while still being easy to take off for maintenance or changing out parts. Machined from high quality steel, hardcoat anodized, and features a QD sling attachment slot. Improve a weak point in the AR system with the Primary Weapons Systems Ratchet Lock Castle Nut and Endplate.


  • Machined from steel
  • Hardcoat anodized
  • Rock solid without staking
  • Easy to remove
  • QD sling attachment slot

The mission at Primary Weapons Systems is to provide the highest quality sporting/tactical rifles and accessories for sportsmen, military, and law enforcement at a fair, competitive price.

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BrandPrimary Weapons Systems
Sling MountQD Sling Swivel
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to www.P65Warnings.ca.gov.

Ratings & Reviews

5 reviews

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Such a simple yet ingenious device.


Staking the castle nut is a pain especially without the right tool, unfortunately the tool is a bit too expensive for me personally. This simple design not only eliminates the need to permanently deform both the carbine tube and castle nut you can also remove it if ever needed. Plus the price cannot be beat.

Theyre OK

by -

These castle nuts initially seemed awesome, but after having several for a while I have found that they eventually come loose. The problem is, they dont actually "ratchet" at all. There is a small metal dimple that is displaced by the force you use to tighten the nut down, and once displaced initially tends to allow the nut to back off with normal use. The remedy is to either A) keep checking and re-torquing these down, or B) just stake the castle nut like you should do in the first place. YMMV, but all 3 of mine have backed off.

Zero chance it comes loose


Not sure what the other reviewer did wrong on install, but there is zero chance this thing comes loose…ZERO

Quality part and functionality

by -

This is a quality end plate and castle nut. I used this on my very first build and have had no issues. I also enjoy the finish on these parts

They work


Used these on 6 builds. I had one back off before I had a castle nut wrench, after I used a wrench and tightened it real good they've never come loose. Would recommend if you don't want to stake.