5 KAC Bolt Carrier Physicals & 1 LMT Enhanced Bolt Physical

This video provides an in-depth autopsy and physical inspection of a Primary Weapons Systems (PWS) bolt carrier group, highlighting significant manufacturing defects. The inspection reveals issues with gas key alignment, staking quality, and dimensional tolerances, leading to the conclusion that the carrier is 'dead on arrival'. The video also includes a physical inspection of an LMT Enhanced Bolt, which passes all tests.

This comprehensive guide details an in-depth autopsy of an AR-15 upper receiver and a SOLGW Scalper Bolt Carrier Group (BCG) to diagnose potential corrosion issues. The process involves detailed visual inspection, borescoping the barrel, and extensive gauging of BCG components. Key findings include worn gas rings, minor pitting on the bolt face, and potential light corrosion in the barrel's rifling, likely stemming from ammunition or environmental factors. The guide emphasizes thorough cleaning and inspection to ensure firearm reliability and longevity.

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 video demonstrates a critical inspection for LMT bolt carrier groups, specifically checking the torque on the carrier key screws. Using a Wheeler FAT Wrench, the instructor performs a breakaway test at 20 and 30 inch-pounds to identify broken or under-torqued screws. The video highlights the importance of this check to prevent potential failures and outlines options for resolution, including contacting the manufacturer or performing a replacement and proper staking.

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.