Receiver Extension Lock Nut by Aero Precision

Ensure a rock-solid connection between your lower receiver and buffer tube with the Receiver Extension Lock Nut by Aero Precision. Built to exacting military specifications and engineered for long-term reliability, this essential component delivers the durability and fitment serious AR builders demand. Whether you’re upgrading a duty rifle or assembling a new custom build, this lock nut ensures your carbine buffer system stays tight and dependable.

Product Description

The Aero Precision Receiver Extension Lock Nut, often referred to as a castle nut, is machined from high-strength steel and finished with a durable phosphate coating. Compatible with both AR15 and AR10 mil-spec platforms, it securely retains the end plate and buffer tube, preventing rotation and loosening during operation. It is designed for use with a standard armorer’s wrench for easy torque and installation. When staked correctly, this lock nut offers a permanent, vibration-resistant hold ideal for tactical, competitive, or duty-grade setups.

Key Features

• Mil-Spec Construction: Designed to meet strict military specifications for guaranteed reliability and compatibility.

• High-Strength Steel: Built from heat-treated steel for superior durability under recoil stress.

• Phosphate Coated Finish: Corrosion-resistant surface provides lasting protection in harsh environments.

• AR15/AR10 Platform Compatibility: Fits standard carbine receiver extensions for both platforms.

• Standard Threading: Designed to work with all standard mil-spec buffer tubes, end plates, and lower receivers.

• Secure Fitment: Prevents buffer tube movement and ensures consistent alignment with the lower receiver.

• Stakable Design: Allows for proper staking to prevent loosening under repeated firing conditions.

• Tool Compatible: Works with all standard castle nut wrenches for quick and secure installation.

Product Specifications

• Material: Hardened steel

• Finish: Phosphate (matte black)

• Compatibility: AR15 and AR10 mil-spec carbine receiver extensions

• Threading: 1-3/16”-16 UN

• Dimensions: Standard mil-spec size

• Weight: Approx. 0.4 oz

• Country of Origin: USA

• Installation: Requires armorer’s wrench and proper staking tool (recommended)

Benefits

• Provides secure attachment of buffer tube and end plate

• Prevents rotation and wear over time

• Corrosion-resistant finish holds up in all weather conditions

• Compatible across a wide range of AR builds

• Easy to install with basic armorer tools

• Critical for safe and functional buffer system performance

Usage Instructions

1. Slide the lock nut onto your buffer tube before installing the end plate.

2. Thread the buffer tube into the receiver until it retains the buffer retainer pin.

3. Slide the end plate forward and hand-tighten the lock nut.

4. Use an armorer’s wrench to torque the lock nut to approximately 38–42 ft-lbs.

5. Stake the end plate into the notches of the lock nut to secure it in place.

Warranty Information

• Manufacturer Warranty: Backed by Aero Precision’s limited lifetime warranty against defects in materials and workmanship.

• Support: U.S.-based customer service team available for technical assistance and product support.

Elevate the integrity of your AR build with the Receiver Extension Lock Nut by Aero Precision — the mil-spec solution for builders who demand dependable performance and secure fitment.