$26.99
6 in stock
Online inventory may differ from in-store availability.
Quick turnaround so you get your gear sooner.
Trusted checkout with industry-standard protection.
Keeping Traditions Alive Since 1953
Secure Transactions provided with 
The castle nut is one of those small parts nobody thinks about until it backs off and your stock starts wobbling. The Armaspec Self-Retention Castle Nut in black takes that headache off the table with a patented thread-locking design that keeps everything tight without staking or a drop of thread locker. It fits standard mil-spec AR-15 and M4 buffer tubes and end plates, so it drops right into most builds without any surprises.
Most castle nuts rely on staking the end plate or gooping up the threads to stay locked under recoil. This one uses a unique thread geometry that grips on its own once you torque it down. That means no permanent modifications, no waiting for compound to cure, and easy removal later if you ever need to pull the buffer tube for maintenance. It is a cleaner setup that saves time on a build and holds up round after round.
Machined from 7075-T6 aluminum, this castle nut tips the scale at right around a quarter ounce, so it trims a little weight at the rear of the rifle without giving up strength. The hardcoat anodized finish adds real corrosion and abrasion resistance, which matters when the gun sees rain, sweat, and hard use in the field. It is made in the USA and backed by an Armaspec lifetime warranty against defects in material and workmanship.
Installation is refreshingly straightforward. Thread it on, torque it to spec, and you are done. No staking punch, no blue Loctite, no second-guessing whether the receiver extension is going to loosen up on you. For anyone assembling their own lower or upgrading a factory build, this is one of those quiet improvements you notice every time the stock stays rock solid.
No. The whole point of this castle nut is that its patented thread design locks in place on its own once torqued down. You skip both the staking step and any thread locker, which also makes future removal a lot easier.
It is machined to fit standard mil-spec AR-15 and M4 receiver extensions and end plates, so it works with the vast majority of common buffer tubes. If your build uses a proprietary or non-mil-spec extension, double check the thread spec before ordering.
It is machined from 7075-T6 aluminum with a hardcoat anodized black finish for corrosion and abrasion resistance. At roughly a quarter ounce, it shaves a bit of weight off the rear of the rifle compared to heavier options while still holding up to high round counts.
Yes. Because there is no staking or thread locker involved, you can back the nut off and reinstall it when you need to pull the receiver extension for cleaning or a swap. That reusability is one of the big advantages over a traditional staked setup.
| UPC | 810048493999 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | ARM6521-BLK |
You must be logged in to post a review.
Reviews
There are no reviews yet.