Carrier & Carrier Key Sealant

Published on April 13, 2020
Duration: 3:11

This guide details the process of replacing bolt carrier group (BCG) key screws and applying sealant for a better gas seal. The video highlights that some manufacturers, like Five Seven Arms, use sealant on the carrier key to ensure a more efficient seal and retain screws. It also discusses potential causes of gas blow-by, such as uneven mating surfaces, and notes that while sealant helps, it may not always eliminate minor blow-by.

Quick Summary

Sealant is applied to AR-15 bolt carrier group carrier keys to enhance the gas seal and help retain screws. While it improves sealing, minor gas blow-by can still occur if mating surfaces have imperfections. Replacing the carrier key when installing new screws is recommended for optimal performance.

Chapters

  1. 00:00Introduction to BCG Carrier Key Sealant
  2. 00:13Why Replace Carrier Keys
  3. 00:31Sealant Application and Purpose
  4. 01:11Understanding Gas Blow-by
  5. 02:00Blow-by and Potential Issues
  6. 02:41Manufacturer Practices and Conclusion

Frequently Asked Questions

Why is sealant used on an AR-15 bolt carrier group's carrier key?

Sealant is applied to the carrier key and bolt carrier mating surfaces to create a more efficient gas seal, preventing blow-by. It also aids in retaining the carrier key screws once they are properly torqued.

What can cause gas blow-by even with a sealed carrier key?

Gas blow-by can occur if the mating surfaces of the bolt carrier or the carrier key are not perfectly flat or true, creating small voids where gas can escape. Even with sealant, significant imperfections can lead to minor leakage.

Should I replace the carrier key when installing new screws?

Yes, it is generally recommended to replace the carrier key when installing new screws. Reusing an old carrier key is not advisable, especially if you are addressing potential sealing issues.

Are all AR-15 bolt carrier groups manufactured with carrier key sealant?

No, not all AR-15 manufacturers apply sealant to the carrier key. Some companies do, while others may only torque and stake the key, with consistency varying across the market.

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