AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available
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- 90-day no-hassle returns policy
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Product description
Secure Your AR15 Buffer Assembly with a Steel Castle Nut
This steel castle nut is an essential piece of an AR15 buffer tube/stock assembly. With standard cuts for use with armorer’s wrench, and smaller cuts for “staking” the castle nut and endplate for a secure hold, this part does everything it should at a good price. If you’re in need of a spare for a new build or replacing a damaged component, this one is right for you. You can also add a little more color to your black rifle with with your choice of Cerakote™ finish. You can choose from FDE, ODG, Pink, Blue, Red, Burnt Bronze, Tungsten, and Titanium.
Specifications
- Material: Steel
- Finish
- Black: Phosphate
- Flat Dark Earth: H-267 Magpul® Flat Dark Earth
- OD Green: H-232 Magpul® OD Green
- Pink: H-224 SIG™ Pink
- Red: H-167 USMC Red
- Blue: H-171 NRA Blue
- Burnt Bronze: H-148 Burnt Bronze
- Tungsten: H-237 Tungsten
- Titanium: H-170 Titanium
- Thread: Mil-Spec
- Compatible with armorer’s wrench
All 9 options on this page
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Black SKU AT3-Castle-01 · UPC 5060748421388
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Burnt Bronze SKU AT3-Castle-01-BB · UPC 5060748422187
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Tungsten SKU AT3-Castle-01-TG · UPC 5060748422194
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Flat Dark Earth SKU AT3-Castle-01-FDE · UPC 5060748421395
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Titanium SKU AT3-Castle-01-TI · UPC 5060748422200
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: OD Green SKU AT3-Castle-01-ODG · UPC 5060748421036
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Pink SKU AT3-Castle-01-PNK · UPC 5060748421050
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Red SKU AT3-Castle-01-RED · UPC 5060748421074
- AT3™ Castle Nut for AR-15 Buffer Tubes - 9 Colors Available - Color: Blue SKU AT3-Castle-01-BLU · UPC 5060748421067
Customer reviews 105
Verified buyer Another ST3 5-Star product!
AT3 Tactical · Thank you for your kind review! We are thrilled to hear that you are happy with the quality and price of our castle nuts. We take pride in offering a variety of colors to choose from as well. Thank you for choosing our product and happy shooting!
AT3 Tactical · Thank you for your kind words! We are so glad to hear that you are happy with the red castle nut and our fast shipping. We strive to provide high-quality products and excellent customer service. Thank you for choosing our company, we truly appreciate your support.
AT3 Tactical · Thank you for your positive review! We are glad to hear that you are satisfied with your purchase of the AT3™ Castle Nut for AR-15 Buffer Tubes. We appreciate your support. Have a great day!
Questions & Answers 1
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Are mil-spec and civilian buffer tube threads the same? I know the tube diameters are different
jack · Mar 21, 2025AT3 Support Team — Mil-spec and commercial buffer tube threads are the same—both use 1-3/16"-16 TPI (threads per inch). This means that the threading where the buffer tube screws into the lower receiver is identical for both types. However, the outer diameter of the buffer tubes differs: Mil-spec buffer tubes have a 1.148" outer diameter and are made from stronger 7075-T6 aluminum. Commercial buffer tubes have a 1.168" outer diameter and are usually made from 6061 aluminum, which is slightly weaker.
Warranty & returns
Backed by the AT3 Lifetime Warranty!
All AT3 Tactical Brand Products carry a lifetime warranty against manufacturer’s defects.
This includes AT3 Red Dot Sights, Handguards, Iron Sights, and any other product that carries the “AT3 Tactical” or “AT3™” name. For other brands (ex. Magpul or Troy), please refer to the manufacturer’s warranty policy.
In the event that your AT3™ product becomes unusable, we will repair or replace the product at no charge to you.
If we cannot repair your product, we will replace it with a product in perfect working order of equal or better physical condition. The warranty is fully transferable, but we may require information about the original purchase to validate the authenticity of the product.
If your product is in need of warranty service, please contact AT3 Tactical to start the process
Our contact info is available here. To expedite processing, please provide your order information and description of the defect.
Please note: The AT3 Lifetime Warranty does not cover loss, theft, intentional damage or cosmetic damage that doesn’t affect the performance of the product.
90-day no-hassle returns
The AT3 Tactical store has a 90 day no-hassle return policy for products in good condition. You can view the full details of our return policy here.
If you encounter an issue or defect with a product after 90 days of your purchase, you can refer to the manufacturer for a warranty claim. Their policies are below.
