7 Sons of Liberty Gunworks Bolt Carrier Physicals

Published on April 18, 2025
Duration: 32:20

This video provides a detailed physical inspection and testing procedure for Sons of Liberty Gunworks bolt carrier groups. The instructor demonstrates how to check for proper fit, dimensions, and potential defects using various gauges and visual inspections. Key tests include gas ring functionality, bolt tail and face fit, carrier length, cam pin fit, firing pin protrusion, and extractor clearance, offering insights into ensuring bolt carrier group reliability and performance.

Quick Summary

A thorough bolt carrier group inspection involves checking gas ring seal, bolt tail and face fit with gauges, carrier length (minimum 6.66 inches), cam pin fit, firing pin protrusion (0.031-0.032 inches), and visual inspection for machining defects. These tests ensure proper function and reliability.

Chapters

  1. 00:00Introduction to BCG Physical
  2. 00:32Gas Ring Test
  3. 01:41Field Stripping BCG
  4. 02:32Bolt Face Inspection (Brass Transfer)
  5. 03:10Bolt Carrier Go/No-Go Test
  6. 04:06Bolt Tail Fit Test (Green/Yellow Gauges)
  7. 06:08Bolt Tail Efficiency Check
  8. 08:59Measuring Bolt Carrier Length
  9. 09:45Carrier Key Inspection
  10. 11:13Inside Bolt Carrier Inspection
  11. 11:55Gas Ring Run Inspection
  12. 13:36Visualizing Finishes
  13. 15:57Carrier Belly Inspection
  14. 16:38Cam Pin Fit Test
  15. 17:05Extractor/Ejector Testing
  16. 18:29Bolt Face and Cam Pin Hole Gauge Test
  17. 20:05Magnetism Checks
  18. 21:16Firing Pin Tip Inspection
  19. 22:29Firing Pin Protrusion and Movement Test
  20. 25:20Bolt Tail Gauge Test (Red/Yellow)
  21. 26:03Firing Pin Hole Inspection
  22. 26:37Cam Pin Gauge Test Explained
  23. 29:18Extractor Clearance Test
  24. 30:34Gas Path Check
  25. 31:09Summary and Enhancements

Frequently Asked Questions

What is the purpose of the brass transfer on a bolt face?

Brass transfer on a bolt face typically indicates that the bolt has undergone high-pressure testing or has been fired with specific ammunition. It's a visual cue that the component has been subjected to stress testing.

How do you check for an undersized bore in a bolt carrier or carrier key?

You can check for an undersized bore by using a 'go' gauge. If the gauge does not fully seat into the bolt carrier or carrier key, it suggests the bore may be undersized, potentially affecting gas system function.

What is the critical length for a bolt carrier, and why is it important?

The critical length for a bolt carrier is generally considered to be not shorter than 6.66 inches. If a carrier is too short, the buffer can follow it too far forward, potentially crashing into the buffer retainer and causing damage.

How can you tell if a cam pin is faulty or worn?

A faulty or worn cam pin can be identified using a specific gauge. If the cam pin, when inserted into the bolt, covers the firing pin bore, it's considered a failure. This indicates excessive looseness, increasing the risk of bolt stretch and breakage.

What is the ideal firing pin protrusion, and what happens if it's incorrect?

The ideal firing pin protrusion is typically between 0.031 and 0.032 inches. If the protrusion is too great, it can punch through primers. If it's too little, it may fail to reliably ignite primers, causing misfires.

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