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Questions & Answers
What Wrench Will Fit Them Standard Wrench Will Not Fit?

I took this to my local gun shop to have it installed, and - no.
It doesn't fit a normal wrench.
He was able to get it on with a normal one though, so it's possible �

by Spaghetti, Verified Owner, April 12, 2026
What is the weight of this item? Expert Answer

It weighs 2 oz.

by Jonathan D., Gear Expert, November 21, 2019
Customer Reviews
Most Recent Reviews
bling bling by Hobie, Verified Owner, July 27, 2025
Very nice chrome plated steel piece. Needed some bling for an AR build. A lot better than those cheap aluminum ones. It is longer also.Very happy with it.
Most Recent Reviews
Castle Nut by Shane87, Verified Owner, September 7, 2024
The black finish on this castle nut is metallic looking & comes off fairly easy but overall it’s aesthetically pleasing.
Most Recent Reviews
I definitely recommend this product. by Romeo, Verified Owner, June 10, 2022
Greatly priced, Looks awesome with a colored buffer tube showing through. Be careful when tightening with your wrench, it can get marred. Definitely will be buying more of these. Shipping was fast as well.
Most Recent Reviews
Terrible design by Add, Verified Owner, April 9, 2022
Just like other guy says won’t work with a lot of buffer tubes I had a WMD and wouldn’t screw on far enough for buffer tube to catch the retainer won’t be able to use. It should have that in the description will I only work with certain buffer tubes
Most Recent Reviews
I purchased this for use with a KAK buffer tube and it did not fit at all! The nut threaded on but, not nearly far enough for the buffer tube to catch the detent. I wound up using this for another project with a standard milspec buffer tube. It did ...
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0/1 found this helpful
Most Recent Reviews
These are cool by Levi Gilkison, Verified Owner, October 19, 2020
Not sure I would label this as "Extreme Duty" as there is probably less actual threads grabbing your buffer tube. However, they look cool for sure! Nice little touch if you're doing a custom build and want those small differences that really set a pa...
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Product Info for Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube

The Guntec USA AR-15 Xtreme Duty Wide Castle Nut, Car/M4 Buffer Tube has been designed to make sure you have the best possible equipment at the ready for all of your shooting needs. The wide design of this AR15 Wide Castle Nut by Guntec USA, makes the area around the buffer tube much less prone to snags and breakage, greatly enhancing the strength and durability of the Nut. The Guntec AR15 Wide Castle Nut Car/M4 Buffer Tube is made with an enhanced design that provides the utmost strength and durability, providing the customer with a quality product at an amazing value that will be long-lasting. For a great way to make sure you are shooting with some of the best possible equipment the rifle industry has to offer, choose the Guntec Wide Rugged Extrme Duty Nut Car/M4 Buffer Tube.image

Specifications for Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube:

Manufacturer: Guntec USA
Gun Model: AR-15
Condition: New
Included Accessories: None
Fabric/Material: Steel
Quantity: each
Length: 1 in
Diameter: 1.375 in

Features of Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube

  • Fits Mil-spec/Commercial Buffer Tubes
  • Enhanced Design For Extreme Strength & Durability

Package Contents:

  • Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube

Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube Orderable Models

List of Orderable Models

  • Guntec USA AR15 Castle Nut Wide Extreme Duty, Black, CASTLE-EXD , MPN: CASTLE-EXD , UPC: 714569646868 , Code: 2AH-CAN-ZCASTLEEXD-CASTLE-EXD
  • Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube, Black Chrome, CASTLE-EXD-BC , MPN: CASTLE-EXD-BC , UPC: 752574658667 , Code: 2AH-CAN-ZCASTLEEXD-CASTLE-EXD-BC
  • Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube, Rainbow Pvd, CASTLE-EXD-RPVD , MPN: CASTLE-EXD-RPVD , UPC: 709016736247 , Code: 2AH-CAN-ZCASTLEEXD-CASTLE-EXD-RPVD
  • Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube, Chrome, CASTLE-EXD-C , MPN: CASTLE-EXD-C , UPC: 709016737213 , Code: 2AH-CAN-ZCASTLEEXD-CASTLE-EXD-C
  • Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube, Matte Rainbow Pvd Coated, CASTLE-EXD-M-RPVD , MPN: CASTLE-EXD-M-RPVD , UPC: 752574658650 , Code: 2AH-CAN-ZCASTLEEXD-CASTLE-EXD-M-RPVD
  • Guntec USA AR-15 Extreme Duty Wide Castle Nut For Car/M4 Buffer Tube, Gold Plated, CASTLE-EXD-GLD , MPN: CASTLE-EXD-GP , UPC: 709016736230 , Code: 2AH-CAN-ZCASTLEEXD-CASTLE-EXD-GP
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