USGI Armorer's Gauges & Tools

This video provides an in-depth inspection of a 60-year-old Colt 601 AR-15 parts kit, utilizing a comprehensive array of USGI and modern gauges. The instructor, identified as a technical expert, meticulously checks various components including the barrel, bolt carrier group, and lower receiver for wear, corrosion, and proper function. The process highlights the importance of specific tools and techniques for assessing the condition of vintage firearms.

This YouTube video from Brownells showcases their AR-15/M16 barrel extension torque tool. It aims to demonstrate the tool's features and highlight the advantages of using it for proper barrel extension installation on AR-15 and M16 platforms. The description encourages viewers to visit the Brownells video website for further information.

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.