Ergo Castle Nut for AR-15 - Secure Your AR Build with Precision in Black - 4971-(B)
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Ergo Grips
Overview
The Ergo Castle Nut for AR-15 is a precision-engineered component designed to securely fasten the buffer tube to the lower receiver, ensuring stability in your build. Made from durable steel and finished in black, this castle nut provides the strength necessary for reliable operation, particularly in builds utilizing a carbine-length gas system with a 5.56 NATO caliber. This part is commonly found in a variety of tactical and sport shooting configurations, making it a staple for builders looking to enhance their AR-15 performance.
Specifications
Ergo Castle Nut for AR-15 - Secure Your AR Build with Precision in Black - 4971-(B)
Available Merchants(5)
Prices checked
Stock Alert
Build history on GunPartPicker
It was in stock most times we checked in October 2026, but today none of the 5 retailers we track has it in stock right now. It dipped to $6 at BattleHawk Armory for a stretch in October 2026, well under its usual $9.49 to $9.99, so sales do come around. Listed prices start at $6 at BattleHawk Armory for when it comes back.
Prices checked · refreshed daily across 37 retailers
Builds Featuring This Part
See all builds →Builds in the community that include the Ergo Castle Nut for AR-15 - Secure Your AR Build with Precision in Black - 4971-(B)
| Build | Parts | Total |
|---|---|---|
 | 24 | $963.97 |
 | 22 | $2336.79 |
 | 25 | $826.38 |
 | 25 | $1388.63 |
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