2 BCM BCG Physicals

This video provides a detailed, expert-level inspection of a Sons of Liberty Gunworks Bolt Carrier Group (BCG). The instructor, a certified Sons of Liberty armoror, walks through numerous tests including gas ring functionality, bolt component integrity, dimensional checks with gauges, magnetic particle inspection, and a critical magazine binding test. The analysis emphasizes the importance of these checks for reliability and longevity, highlighting specific features like the five-coil extractor spring and chrome silicone ejector spring.

This video provides a detailed physical inspection and reassembly guide for an AO Precision Bolt Carrier Group (BCG). The instructor, from School of the American Rifle, highlights common issues like a protruding ejector roll pin and undersized extractor pockets, demonstrating how to correct them. The guide covers disassembly, component inspection, spring replacement, and reassembly, emphasizing proper tool usage and attention to detail for a functional BCG.

This guide details the inspection of an AR-15 bolt carrier group (BCG) after extensive use, focusing on identifying wear and potential failure points. It covers checking the bolt, gas rings, extractor, firing pin, and bolt carrier for stress fractures, damage, and carbon buildup. The video emphasizes that parts wear out over time and regular inspection is crucial for maintaining reliability, especially after high round counts exceeding 30,000 rounds.

This video demonstrates an inspection of a PSA M16 Phosphate/Chrome BCG using a reject gauge. The BCG fails the gauge test, indicating dimensional issues that could lead to premature wear or cracking. A Microbest BCG is shown for comparison, which passes the gauge test.

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.

This video provides an 'abbreviated autopsy' of a KAK K-SPEC Bolt Carrier Group (BCG), focusing on two potential issues: the surface finish of the sand cut rails and the design of the dual ejectors. The instructor highlights that rough sand cut rails can aggressively wear the upper receiver's anodizing or coating. Additionally, the dual ejectors on this specific BCG are noted to have a concave surface, which can dig into brass more aggressively, and they do not retract flush, potentially causing friction and brass material buildup. The owner is advised to contact KAK for resolution.

This guide details the process of diagnosing and repairing an owner-induced feeding problem in an AR-15 upper receiver, specifically addressing a burr on the barrel extension's feed ramp. Expert gunsmith Chad Albrecht demonstrates meticulous inspection, burr removal, and polishing techniques to restore reliable feeding. The video emphasizes that such modifications, while often overlooked, are valid solutions for specific AR-15 malfunctions.

This guide details a diagnostic technique for AR-15 bolt carrier groups, focusing on efficiency rather than simple pass/fail. Developed by Chad Albrecht of School of the American Rifle, it uses custom gauges and cutaway components to illustrate gas dynamics, critical seals, and potential failure points like gas leaks. This advanced method helps troubleshoot functionality issues and understand the nuances of the AR-15's internal gas system.

This video provides a critical, expert-level inspection of a problematic AR-15 Bolt Carrier Group (BCG) by Chad Albrecht of School of the American Rifle. The analysis details numerous manufacturing defects, including an undersized bolt tail, excessive firing pin protrusion, oversized firing pin and cam pin holes, and a failing headspace check. The content highlights the importance of precision gauging in identifying critical failure points that impact rifle reliability and safety.

This guide details a specialized technique for swapping an AR-15 rear takedown pin without requiring a full disassembly. It leverages insights from Chad Albrecht of School of the American Rifle, emphasizing the use of a modified 1/16 inch Allen wrench or a specialized tool to manage the detent. This method is particularly useful for AR-15 variants with collapsible stocks, offering a more efficient approach to maintenance.