Geissele BCG Physical

Published on February 20, 2020
Duration: 14:20

This guide details a comprehensive physical inspection of a new Geissele REBCG, focusing on quality control and tolerances. Expert insights cover coating, component fit, critical measurements like firing pin protrusion and carrier length, and gas key staking. The process emphasizes meticulous examination using specialized tools to ensure optimal performance and reliability, reflecting the speaker's master-level knowledge of AR-15 mechanics.

Quick Summary

Expert inspection of the Geissele REBCG focuses on critical tolerances and quality control. Key checks include firing pin protrusion (ideal at 0.0325 in), gas key staking, bolt-to-carrier fit, and ensuring components are MP/HPT tested. Minor issues like a protruding ejector roll pin are identified and addressed.

Chapters

  1. 00:00Introduction to Geissele REBCG
  2. 00:56Initial Impressions and Coating
  3. 01:51Disassembly and Component Inspection
  4. 03:11Extractor and Ejector Gauging
  5. 04:41Ejector Spring and Bolt Markings
  6. 05:51Firing Pin Inspection and Protrusion
  7. 07:01Gas Key and Staking
  8. 07:41Reverse Torque Test
  9. 08:36Headspace and Carrier Length
  10. 10:31Three-Bore and Gas Efficiency
  11. 12:46Alignment and Final Checks

Frequently Asked Questions

What are the key quality indicators for a Geissele REBCG?

Key indicators include a smooth DLC/Nano coating, proper gas key staking, precise firing pin protrusion (around 0.0325 in), tight bolt-to-carrier fit, and clear MP/HPT markings. The absence of YFS brand screws on the gas key is also noted positively.

How is the firing pin protrusion measured and what is the ideal range?

Firing pin protrusion is measured with a digital gauge. The ideal range is typically below 0.036 inches, with a measurement of 0.0325 inches considered optimal for reliable ignition without excessive wear.

What potential issues should be checked during a physical inspection of the Geissele REBCG?

Potential issues include a slightly protruding ejector roll pin, which could cause snags, and ensuring the gas key screws are properly staked and torqued. Minor machining grooves on the carrier belly are usually non-problematic.

What tools are essential for inspecting a Geissele REBCG?

Essential tools include a digital caliper for measuring carrier length, a digital gauge for firing pin protrusion, an armorer's gauge for gas key alignment, and a pick for examining small components like the ejector roll pin.

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