2 KAK BCG's - Bent/Damaged Extractor Pins

Published on January 10, 2025
Duration: 2:51

This video addresses common issues found in two KAK bolt carrier groups (BCGs), specifically focusing on damaged extractor pivot pins. The instructor demonstrates how rolled-over pins prevent proper extractor function and require replacement. Additionally, rough surface finishes in the carrier key tunnel bore are highlighted as potential causes of premature wear and cycling issues.

Quick Summary

Two KAK bolt carrier groups (BCGs) were examined, revealing damaged extractor pivot pins that required replacement due to being rolled over and seizing the extractor. Rough surface finishes were also noted in the carrier key tunnel bore and the BCG's opening, which can cause premature wear and cycling problems.

Chapters

  1. 00:01Introduction and Follow-up
  2. 00:05Two KAK BCGs: K-Spec and M-Spec
  3. 00:30Extractor Issues Identified
  4. 01:02Damaged Extractor Pivot Pin Example
  5. 01:19Second BCG Extractor Pin Damage
  6. 01:36Replacement of Extractor Pins
  7. 01:41Rough Mouth/Opening on BCG
  8. 02:06Rough Carrier Key Tunnel Bore
  9. 02:19Consequences of Rough Surfaces
  10. 02:30Conclusion and Summary

Frequently Asked Questions

What common problems were found on the KAK bolt carrier groups in this video?

The primary issues identified were damaged extractor pivot pins, which were rolled over and prevented the extractor from moving freely. Additionally, both BCGs exhibited rough surface finishes, particularly in the carrier key tunnel bore and the 'mouth' of the bolt carrier group.

How can damaged extractor pivot pins affect a bolt carrier group's function?

When an extractor pivot pin is damaged or peened over, it can seize the extractor, preventing it from moving correctly. This can lead to extraction failures, where spent casings are not properly ejected from the firearm's chamber.

What are the potential consequences of a rough carrier key tunnel bore in a bolt carrier group?

A rough carrier key tunnel bore can cause premature wear on the gas tube. It can also lead to cycling issues, as fouling can stick to the rough surfaces, potentially causing the firearm not to function reliably, especially when dirty.

What steps are involved in fixing a damaged extractor pivot pin on a bolt carrier group?

Fixing a damaged extractor pivot pin typically involves carefully removing the old, damaged pin, which may require significant force. A new, properly sized pin is then installed to allow the extractor to move cleanly and function as intended.

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