The Guntec USA Heavy Duty castle nut is a wide castle nut for AR-15 buffer tubes with an extra-wide body for a stronger, more durable hold. It fits both mil-spec and commercial buffer tubes. Made from steel with a nitride finish in the USA.
- Brand: Guntec USA
- Type: Heavy Duty wide castle nut
- Fits: Mil-spec and commercial AR-15 buffer tubes
- Material: Steel
- Finish: Nitride
- Made in USA
- Manufacturer part number: CASTLE-HD
