Fortis Castle Nut, Black, Anodized Finish, Mil Spec
Fortis Manufacturing
Overview
The Fortis Castle Nut is a standard type castle nut finished in a hardcoat anodized black, providing durability and a sleek appearance for your AR-15 build. This component securely fastens the buffer tube to the lower receiver, ensuring proper alignment and function of the recoil system. It’s commonly found in builds that feature a mid-length gas system chambered in 5.56 NATO, making it a reliable choice for those configurations.
Specifications
Available Merchants(6)
Prices checked
Price Alert
Build history on GunPartPicker
It was in stock most times we checked in October 2026, but today 2 of the 6 retailers we track have it in stock. Prices barely moved in October 2026, holding around $11.35, with no real sale all month. Buying today, the lowest price is $11.35 at Optics Planet, which matches the best price we saw in October.
Prices checked · refreshed daily across 37 retailers
Builds Featuring This Part
See all builds →Builds in the community that include the Fortis Castle Nut, Black, Anodized Finish, Mil Spec
| Build | Parts | Total |
|---|---|---|
 | 13 | $754.72 |
 | 21 | $807.51 |
 | 24 | $819.46 |
 | 23 | $1022.34 |
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