AR-15 Bolt Carrier and Rifle Cut Away Demonstration

This video from School of the American Rifle highlights critical manufacturing defects in AR-15 bolt carrier keys, specifically focusing on rough internal bores. Lead instructor demonstrates how a poorly finished carrier key can cause significant friction, premature wear on components like gas tubes, and operational issues, contrasting a problematic new Colt carrier with a well-functioning older model. The expert emphasizes the importance of a smooth bore for reliable function and longevity of expensive parts.

This guide details the process of diagnosing and fixing a significant rail wobble issue on a new Daniel Defense Mk18 upper receiver. The primary cause identified was a hand-tight barrel nut, compromising the stability of the RIS II rail system. The steps involve disassembly, inspection of the barrel nut, proper tightening with an armorer's wrench and torque wrench, and reassembly. This addresses a critical quality control failure that can affect firearm accuracy and reliability.

This video demonstrates the cleaning and restoration of a heavily fouled Daniel Defense Bolt Carrier Group (BCG) using the Tactical Elites gun cleaning kit. It covers step-by-step disassembly, thorough scrubbing to remove carbon buildup, and meticulous reassembly. The process highlights the importance of proper firearm maintenance for preserving component integrity and functionality, showcasing the effectiveness of the cleaning kit.

This YouTube video focuses on carbon fiber barrels for firearms. It will likely delve into the material's properties, advantages, and potential applications in firearm design and manufacturing. Expect discussions on weight reduction, stiffness, and performance benefits compared to traditional barrel materials. The video may also touch upon different types of firearms that can utilize carbon fiber barrels, such as rifles and pistols, and the impact on shooting accuracy and recoil management.

This guide details the evolution of AR-15 carrier key staking from early 'Gen 1' square staking to modern 'Gen 5' OCKS with serrated heads. It emphasizes proper torque values (vintage 35-40 in-lbs, modern 55-58 in-lbs) and the importance of sufficient metal displacement for screw security. The video, presented by an expert from School of the American Rifle, critiques commercial staking and references historical technical manuals.

This entry details the unique XR-86 custom rifle, a 1986 build by Wilfred Ellis. It masterfully combines components from an M60 (flash hider), an M14 (gas system), and an AR-15 (trigger, bolt, locking system). The AR-15 trigger is notably rotated 90 degrees, and its bolt is integrated with the M14 gas system, showcasing advanced gunsmithing.

This video details the diagnosis and repair of a feeding issue on a Sons of Liberty Gun Works East India upper receiver. The root cause was identified as a sharp burr on the barrel extension's feed ramp, causing rounds to jam. The solution involved polishing the feed ramps and adding a secondary bevel, replicating Colt's design, which successfully resolved the malfunction.

This video provides a detailed autopsy of a faulty AR-15 Bolt Carrier Group (BCG). The analysis reveals critical manufacturing defects including an undersized bolt tail failing gauges, excessive firing pin protrusion causing pierced primers, an oversized firing pin hole, and an oversized cam pin hole leading to headspace issues. These flaws significantly compromise the BCG's function and reliability.

This video demonstrates a specialized technique for swapping an AR-15 rear takedown pin without full firearm disassembly. It highlights the use of a custom-fabricated tool, often made from a 1/16 inch Allen wrench, to depress the detent. The method allows for efficient pin replacement, particularly useful on rifles with staked castle nuts, by leveraging the old pin to guide the new one into place.

This video details the autopsy and repair of a Black Rain Ordnance SPEC15 AR-15, focusing on addressing an over-gassed system. Key upgrades include a BRT EZTUNE gas tube, Sprinco buffer spring and extractor/ejector springs, and a JP titanium firing pin. The process involves meticulous reassembly with specific torque values and the use of Loctite 620 for barrel bedding, resulting in a properly tuned gas system.