Anderson Manufacturing BCG Autopsy - Sheared Lug after 150 Rounds

Published on October 14, 2025
Duration: 2:02

This video provides an abbreviated autopsy of an Anderson Manufacturing Bolt Carrier Group (BCG) that experienced a unique failure: a sheared lug near the ejector after only 150 rounds. The instructor notes that typical lug failures occur near the extractor due to higher load. While the carrier key screws passed a breakaway test, the carrier key itself leaked, indicating poor efficiency. The instructor emphasizes checking all firearm components regardless of manufacturer.

Quick Summary

An Anderson Manufacturing Bolt Carrier Group (BCG) experienced a unique failure with a sheared lug near the ejector after only 150 rounds. While typical AR-15 lug failures occur near the extractor due to higher loads, this case was unusual. The BCG also showed a leaking carrier key, indicating poor efficiency.

Chapters

  1. 00:00Introduction and BCG Overview
  2. 00:22Unique Sheared Lug Failure
  3. 00:39Typical Lug Failure Points
  4. 00:47LMT Enhanced Bolt Design
  5. 00:52Sheared Lug Near Ejector
  6. 01:01Visualizing the Ejector Through Sheared Lug
  7. 01:11Bin of Shame and Replacement
  8. 01:23Other BCG Observations
  9. 01:30Carrier Key Sealant and Efficiency
  10. 01:42Importance of Checking All Components
  11. 01:50Conclusion and Educational Value

Frequently Asked Questions

What is a unique failure mode observed in the Anderson Manufacturing BCG?

The Anderson Manufacturing BCG in this video exhibited a unique failure where a lug sheared off near the ejector. Typically, AR-15 bolt lugs shear near the extractor due to higher operational loads.

What are the common locations for lug shearing on an AR-15 bolt?

On most AR-15 bolts, lugs shear either to the right or left of the extractor. This is because these areas experience the most significant load during the firing cycle.

What other issues were noted with the Anderson Manufacturing BCG besides the sheared lug?

Besides the sheared lug, the BCG had a carrier key that leaked, indicating poor efficiency, and lacked sealant on the carrier key. However, the carrier key screws did pass a breakaway test.

Why is it important to check firearm components regardless of the manufacturer?

The video highlights that while some Anderson BCGs may have issues, others function without problems. This underscores the necessity of inspecting all firearm components for damage or wear, irrespective of brand, to ensure safe and reliable operation.

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