Tech Tip: How To Replace an AR-15 Gas Key

Published on May 10, 2023
Duration: 32:12

This expert guide from Brownells details the critical process of replacing an AR-15 gas key. Instructor Caleb emphasizes meticulous cleaning, precise surface preparation using India stones, and correct installation with Loctite 638 and specific torque values (50-58 inch-pounds) for Grade 8 screws. The final staking procedure ensures long-term reliability by mechanically locking the screws, preventing gas leaks and cycling malfunctions.

Quick Summary

Replace an AR-15 gas key by first breaking factory stakes, then thoroughly cleaning the carrier. Lap the new key flat on an India stone, apply Loctite 638 retaining compound, and install Grade 8 screws torqued to 50-58 inch-pounds. Finally, stake the screws using a jig to prevent loosening.

Chapters

  1. 00:00Introduction: Gas Key Function & Importance
  2. 01:24Removing the Old Gas Key Screws
  3. 02:43Inspection and Cleaning the Carrier
  4. 05:46Surface Prep: Lapping the New Gas Key
  5. 07:51Applying Retaining Compound & Oiling Screws
  6. 09:56Torquing and Staking the Gas Key

Frequently Asked Questions

What is the correct torque specification for AR-15 gas key screws?

The recommended torque specification for AR-15 gas key screws is between 50 and 58 inch-pounds. It's crucial to use a calibrated torque driver and Grade 8 fasteners for proper installation and reliability.

Why is staking an AR-15 gas key important?

Staking is essential because it mechanically locks the gas key screws in place, preventing them from vibrating loose due to recoil and firing. This ensures a consistent gas seal and prevents malfunctions.

What type of adhesive should be used when installing an AR-15 gas key?

A high-strength retaining compound, such as Loctite 638, is recommended for the mating surface of the gas key. This fills microscopic gaps and ensures a gas-tight seal, unlike standard thread lockers.

How do you ensure a proper gas seal when replacing an AR-15 gas key?

Achieving a proper gas seal involves meticulous cleaning and degreasing of the carrier surface, lapping the new gas key flat using India stones, applying Loctite 638 retaining compound, and correctly torquing and staking the screws.

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