Loctite 620 on an AR?

Published on June 18, 2024
Duration: 2:15

This video from School of the American Rifle demonstrates the application of Loctite 620, a sleeve retaining compound, for specific AR-15 build and maintenance tasks. It details its use in bedding barrels to upper receivers and securing the carrier key to the bolt carrier, noting it as an improvement over standard methods. The instructor emphasizes proper application amounts, cleanup, and cure times for optimal performance and gas system efficiency.

Quick Summary

Loctite 620 is applied to AR-15s as a sleeve retaining compound for barrel bedding to the upper receiver and for securing the carrier key to the bolt carrier. This application aims to improve component contact and potentially enhance gas system efficiency. Proper application involves small amounts, avoiding critical threads, and cleaning any excess from gas paths. It requires an overnight cure, which can be accelerated by heat.

Chapters

  1. 00:00Introduction to Loctite 620
  2. 00:19Where Loctite 620 is Used
  3. 00:22Carrier Key Application
  4. 00:34Barrel Bedding Application
  5. 00:47Application Amounts
  6. 00:58Carrier Key Application Details
  7. 01:10Cure Time and Acceleration
  8. 01:27Benefits of Using Loctite 620
  9. 01:35Cleaning the Gas Path
  10. 01:45Carrier Key Preparation
  11. 01:56Summary of Applications

Frequently Asked Questions

What is Loctite 620 used for on an AR-15?

Loctite 620 is used as a sleeve retaining compound on AR-15s for two primary applications: bedding the barrel to the upper receiver and securing the carrier key to the bolt carrier. These uses aim to improve component contact and potentially enhance gas system efficiency.

How much Loctite 620 should be applied to an AR-15 barrel for bedding?

For barrel bedding, a small amount of Loctite 620 is applied to the chamber end of the barrel where it interfaces with the upper receiver. It's crucial to avoid applying it to the barrel nut threads to prevent installation issues.

What is the cure time for Loctite 620 on firearm components?

Loctite 620 typically requires an overnight cure (around 24 hours) for full setting. The curing process can be accelerated by heating the components to approximately 200°F, which allows it to semi-set more quickly.

Why is it important to clean Loctite 620 from the carrier key gas path?

It is critical to remove any excess Loctite 620 from the carrier key gas path to ensure unobstructed gas flow. If the sealant oozes into this channel, it can impede the function of the bolt carrier group and negatively affect the firearm's operation.

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