Lbe Unlimited115667228
LBE Unlimited AR-10 Barrel Nut 4130 Steel Black Phosphate ARBNT308$19.91
Availability: In Stock
The LBE Unlimited AR-15 castle nut is a critical buffer tube component built from 4140 steel and finished in black phosphate—a durable, corrosion-resistant coating that holds up to field use and regular handling. Whether you're assembling a new rifle, upgrading a lower receiver, or replacing a worn stock hardware set, this castle nut threads onto the buffer tube to secure your buttstock and keep everything locked in place during firing and handling. Made in the USA, it's a no-nonsense part that does its job without fanfare.
Castle nuts are easy to overlook until you need one—and when you do, having the right fit matters. This LBE unit is engineered to AR-15 spec, so it threads cleanly and sits flush when properly torqued. The 4140 steel construction provides the strength needed to handle repeated assembly and disassembly cycles, and the black phosphate finish resists rust and corrosion better than bare steel, especially in humid or wet environments.
If you're building an AR from a lower receiver kit or maintaining an existing rifle, keeping a spare castle nut on hand is smart practice. They're inexpensive insurance against stripped threads or damage during field takedown. Pair it with a proper armorers wrench for installation—you'll want even pressure to avoid cross-threading or deformation.
| Material | 4140 Steel |
| Finish | Black Phosphate |
| Compatibility | AR-15 Buffer Tube |
| Manufacturer | LBE Unlimited |
| Country of Origin | USA |
This castle nut is designed to fit standard AR-15 buffer tubes. Confirm your rifle uses a mil-spec or commercial buffer tube before ordering if you have a non-standard lower receiver.
Yes—you'll need an armorers wrench or castle nut wrench to install and remove it properly. Hand-tightening alone won't seat it securely, and you want even pressure to avoid damaging the tube or nut.
The black phosphate coating provides corrosion resistance and a clean, finished appearance. It's more durable than bare 4140 steel in storage, field conditions, and humid environments.
Yes. As long as the threads aren't damaged and the finish isn't compromised, you can reinstall it during reassembly.
SKU: 115744254 • Width: 2.8in • Height: 0.6in • Depth: 4in • Weight: 0.06oz
Availability: In Stock
The LBE Unlimited AR-15 castle nut is a critical buffer tube component built from 4140 steel and finished in black phosphate—a durable, corrosion-resistant coating that holds up to field use and regular handling. Whether you're assembling a new rifle, upgrading a lower receiver, or replacing a worn stock hardware set, this castle nut threads onto the buffer tube to secure your buttstock and keep everything locked in place during firing and handling. Made in the USA, it's a no-nonsense part that does its job without fanfare.
Castle nuts are easy to overlook until you need one—and when you do, having the right fit matters. This LBE unit is engineered to AR-15 spec, so it threads cleanly and sits flush when properly torqued. The 4140 steel construction provides the strength needed to handle repeated assembly and disassembly cycles, and the black phosphate finish resists rust and corrosion better than bare steel, especially in humid or wet environments.
If you're building an AR from a lower receiver kit or maintaining an existing rifle, keeping a spare castle nut on hand is smart practice. They're inexpensive insurance against stripped threads or damage during field takedown. Pair it with a proper armorers wrench for installation—you'll want even pressure to avoid cross-threading or deformation.
| Material | 4140 Steel |
| Finish | Black Phosphate |
| Compatibility | AR-15 Buffer Tube |
| Manufacturer | LBE Unlimited |
| Country of Origin | USA |
This castle nut is designed to fit standard AR-15 buffer tubes. Confirm your rifle uses a mil-spec or commercial buffer tube before ordering if you have a non-standard lower receiver.
Yes—you'll need an armorers wrench or castle nut wrench to install and remove it properly. Hand-tightening alone won't seat it securely, and you want even pressure to avoid damaging the tube or nut.
The black phosphate coating provides corrosion resistance and a clean, finished appearance. It's more durable than bare 4140 steel in storage, field conditions, and humid environments.
Yes. As long as the threads aren't damaged and the finish isn't compromised, you can reinstall it during reassembly.
SKU: 115744254 • Width: 2.8in • Height: 0.6in • Depth: 4in • Weight: 0.06oz