Bootleg Adjustable BCG Physical

Published on March 4, 2020
Duration: 15:16

This video provides a detailed physical inspection of a Bootleg adjustable bolt carrier group (BCG). The instructor examines various components including the bolt, firing pin, extractor, and carrier key, performing critical measurements like headspace and firing pin protrusion. Key findings include poor staking of the carrier key fasteners (YFS fasteners), potential nickel boron coating on the firing pin, and a rough bolt face. The video also demonstrates testing the integrity of the YFS fasteners under torque and checking for gas leakage.

Quick Summary

This Bootleg adjustable BCG inspection revealed poor carrier key staking and brittle YFS fasteners that broke at 50 inch-pounds of torque. While headspace passed, firing pin protrusion was at the minimum .028 inches, and the bolt face had rough machining marks. The carrier key seal showed slight gas leakage.

Chapters

  1. 00:00Introduction to Bootleg Adjustable BCG
  2. 00:15Unique Features of the BCG
  3. 00:28Initial Observations: Nickel Boron Bolt
  4. 00:49Carrier Key Staking and Fastener Issues
  5. 01:30Firing Pin Retaining Pin and Firing Pin Inspection
  6. 02:05Bolt Removal and Inspection
  7. 02:11Extractor Removal and Inspection
  8. 02:44Bolt Gauging (No-Go and Go)
  9. 03:00Firing Pin Protrusion and Travel Check
  10. 03:33Headspace Check (.223/5.56)
  11. 04:15Firing Pin Hole Inspection
  12. 04:42Magnetism Check
  13. 05:09Gas Ring Inspection
  14. 05:16Extractor Go/No-Go Gauge Test
  15. 05:32Pivot Pin and Cam Pin Inspection
  16. 06:12Carrier Measurements
  17. 06:52Carrier Key Inspection
  18. 07:41Bolt Shoulder, Bolt Support, and Gas Ring Gauging
  19. 09:05Bolt Tail Run Gauging
  20. 09:33YFS Fastener Torque Test
  21. 11:00Gas Leakage and Copper Residue Check
  22. 12:08Cam Pin Contact Marks
  23. 12:53Adjustable Gas System Inspection
  24. 14:05Conclusion and Next Steps

Frequently Asked Questions

What are the main concerns with the staking on this Bootleg adjustable BCG?

The staking job on this Bootleg adjustable BCG is considered poor, appearing to be done with a chisel. This method is not ideal and can lead to fastener failure under the stress and shock experienced by a bolt carrier group during operation.

What issues were found with the YFS fasteners used on the carrier key?

The YFS fasteners used on the carrier key are noted as being brittle despite their strength. Testing showed they broke at 50 inch-pounds of torque, indicating a potential failure point under the operational shock and load of an AR-15.

What were the results of the headspace check on this BCG?

The headspace check for .223/5.56 caliber was performed using both go and no-go gauges. The BCG passed these checks, meaning the bolt correctly closed on the go gauge and did not close on the no-go gauge, indicating proper chamber fit.

What is the significance of the firing pin protrusion measurement?

The firing pin protrusion was measured at .028 inches. This is at the bare minimum acceptable limit for an AR-15. While it passed, it's on the lower end, and a tighter tolerance is generally preferred for reliable ignition.

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