AR Bolt Tail Gauges - AKA Gas Efficiency Gauges

This expert guide from the School of the American Rifle details how to identify and address rough carrier key bores in AR-15 bolt carrier groups. The instructor, demonstrating expert knowledge, explains how these manufacturing defects, particularly on Colt components, can lead to premature wear on the gas tube and reduced reliability. Solutions involve replacing the defective carrier key to ensure smooth operation and longevity of the firearm.

This guide details the process of lapping an AR-15 receiver to ensure proper barrel alignment for improved long-range accuracy. Instructor Stephen Caleb from Brownells explains that receiver faces can be slightly out of alignment, leading to barrel runout. The process involves using a specialized lapping fixture and aluminum oxide lapping compound with a drill to create a perfectly flat receiver face. This ensures the barrel seats flush and square, critical for precision shooting beyond 500 yards.

This guide details the process of replacing the buffer and spring assembly in an AR-15 platform rifle. It covers disassembly, removal of the old components, installation of new parts like the Kynshot RB5000 hydraulic buffer or the Geissele Super 42 system, and reassembly with a function check. The video emphasizes proper technique and the benefits of upgraded components for recoil management and reliability.

This guide details the cleaning process for the VKTR VK1's Bolt Carrier Group (BCG), emphasizing the unique patented cam path. The video highlights the BCG's thin dense chrome finish and its role in reliability. Proper maintenance ensures the longevity and performance of this piston-driven AR.

This guide details the installation of several popular AR-15 upgrades featured in the video: the Aero Precision Breach Charging Handle, Die Free Co Kung Fu Grip, and Superlative Arms Adjustable Gas Block. It emphasizes proper installation and tuning, particularly for .300 Blackout builds, drawing on the instructor's high authority and knowledge of AR-15 components.

This guide demonstrates the proper installation of a suppressor onto an AR-style rifle using a direct thread method. It emphasizes a secure fit and highlights the visual steps involved in attaching the suppressor to the barrel. The video, from AT3 Tactical, focuses on ensuring the suppressor is correctly mounted for optimal performance and safety.

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.