LBE Unlimited Barrel Nut — 4130 Steel, Black Phosphate — AR-10 (Model ARBNT308, UPC: 784682014370)
Upgrade your AR-10 build with an industry-grade barrel nut engineered for durability, repeatable torque, and rock-solid alignment. The LBE Unlimited Barrel Nut (ARBNT308) is manufactured from premium 4130 chromoly steel, finished in protective black phosphate, and designed specifically to meet the dimensional and strength demands of modern .308/AR-10 platforms. Whether you’re assembling a precision rifle, a heavy-use patrol firearm, or a competition build, this barrel nut delivers the stability and longevity your upper receiver requires.
Key Features & Benefits
Material: 4130 Chromoly Steel — exceptional toughness and fatigue resistance for long-term reliability.
Finish: Black phosphate — corrosion-resistant, low-glare surface that holds up in harsh environments.
Compatibility: Designed to fit AR-10/.308 upper receivers and standard .308-length barrels that require an AR-10-spec barrel nut.
Precision Threads: Factory-cut threads for accurate fit and repeatable installation without stress or deformation.
Torque Stability: Engineered to maintain proper headspace and torque under repeated firing and thermal cycling.
Durable Construction: Withstands frequent installation, removal, and re-torquing without galling or thread damage.
Weight: Optimized for strength-to-weight balance—sturdy where it matters, without excess mass.
Why LBE Unlimited Barrel Nut?
A barrel nut is a small part with a big job: it secures the barrel to the upper receiver and sets the foundation for gas system alignment, handguard mounting, and overall accuracy. LBE Unlimited built the ARBNT308 to exacting tolerances so your barrel seats squarely, your gas tube aligns reliably, and your free-floated handguard indexes consistently. The result is a rifle that keeps zero, reduces stress on mating components, and provides a rock-solid platform for optics and accessories.
Performance You Can Trust
4130 chromoly offers a superior combination of tensile strength and toughness compared to common mild steels used in budget components. When paired with a black phosphate finish, the barrel nut resists corrosion while offering a low-reflective surface—ideal for tactical applications and match-grade rifle builds. The ARBNT308 maintains torque and alignment under heat and sustained fire, making it an excellent choice for semi-automatic and sustained-fire scenarios.
Installation & Compatibility Notes
Fits: AR-10 / .308 pattern upper receivers that accept an AR-10 style barrel nut.
Tools Required: Proper torque wrench and armorer’s wrench with compatible barrel nut flats. Follow manufacturer torque specifications for your barrel and receiver.
Gas Systems: Compatible with various gas tube lengths and gas block setups—ensure correct gas tube alignment before final tightening.
Handguards: Supports most free-float barrel nut-mounted handguards and rail systems designed for AR-10 indexing. Some proprietary handguards may require specific nut types—verify compatibility.
Headspace & Safety: Always verify headspace and function after installation by a qualified gunsmith or armorer.
Ideal For
Precision AR-10 builds and hunting rifles
Competition shooters requiring repeatable mounting geometry
Law enforcement and duty rifles where durability matters
DIY builders and experienced armorers upgrading or repairing rifles
Anyone who values high-quality, American-style manufacturing standards in key rifle components
Technical Specifications
Model: ARBNT308
Manufacturer: LBE Unlimited
Material: 4130 Chromoly Steel
Finish: Black Phosphate
Platform: AR-10 / .308
UPC: 784682014370
Included: 1 × LBE Unlimited Barrel Nut (ARBNT308) — additional hardware (washers, shoulder screws) may be required depending on your handguard/receiver system.
Maintenance & Care
To maximize lifespan: periodically inspect threads for wear, apply a thin film of anti-seize or appropriate lubricant during installation to prevent galling, and keep the finish clean and dry after exposure to moisture or corrosive firing residues. Replace if thread damage or distortion is detected.
What’s in the Box
Final Thoughts
The LBE Unlimited Barrel Nut (ARBNT308) is a no-compromise component for AR-10 builders who demand strength, repeatability, and corrosion resistance. Made from rugged 4130 steel and finished in black phosphate, this barrel nut offers the dependable foundation every precision or duty rifle needs. If you’re assembling a .308 platform and want a part engineered to last and perform, the ARBNT308 is an essential upgrade for durability, alignment, and long-term function.
The End
