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Fortis Manufacturing
Overview
The Fortis Light Weight K1 Castle Nut and End Plate in Flat Dark Earth is an enhanced type designed for secure attachment of the buffer tube to the lower receiver. This component features a lightweight construction that minimizes additional weight on your build without sacrificing durability, making it ideal for streamlined setups. It commonly appears in mid-length gas system builds chambered in 5.56 NATO, where performance and weight savings are key priorities.
Fortis Light Weight K1 Castle Nut and End Plate Black, Flat Dark Earth - LEBLKK1FDE
Builders on GunPartPicker first added the Fortis Light Weight K1 Castle Nut and End Plate Black, Flat Dark Earth - LEBLKK1FDE to a build in January 2026.
It was hard to find in August 2026, in stock on only 2 of the 10 days we checked, and today all 3 retailers we track have it in stock. Prices barely moved in August 2026, holding around $37.95, so there haven't been real sales lately. Buying today, the lowest price is $37.95 at BattleHawk Armory, which matches the best price we saw in August.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 31 retailers
Builds in the community that include the Fortis Light Weight K1 Castle Nut and End Plate Black, Flat Dark Earth - LEBLKK1FDE
| Build | Parts | Total |
|---|---|---|
 | 22 | $2258.48 |
 | 26 | $4668.66 |
 | 26 | $1853.78 |
 | 26 | $1767.17 |
 | 22 | $1017.75 |
 | 27 | $3764.29 |
 | 32 | $5953.09 |
 | 21 | $1295.00 |
| 17 | $943.86 |
 | 27 | $1572.54 |
| 16 | $652.12 |
 | 25 | $2852.39 |
2 global ratings
Top reviews
end plate has a built in QD socket which i used for a blue force gear sling. castle nut threads were clean. lighter than the standard combo by a noticeable amount on a kitchen scale, every gram counts on a lightweight build
Fortis K1 lightweight castle nut and end plate combo in FDE drops in to a milspec lower without any modification. Castle nut has the larger wrench notches. End plate has integrated QD socket. FDE matches Magpul tan well.
