AR-15 Pivot Pin Swap... By Sam Elliott?!!

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 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 video provides a comprehensive, step-by-step guide to building a .300 Blackout AR-15 pistol. Caleb from Brownells walks viewers through the entire process, from selecting top-tier components from manufacturers like Aero Precision and Sons of Liberty Gun Works, to detailed assembly of the lower receiver, upper receiver, gas system, and the installation of accessories such as optics and lights. The guide offers valuable tips on essential techniques like staking castle nuts and setting torque specs, making it an ideal resource for both novice builders and those seeking to learn more about AR-15 customization.

Elliott Delp showcases his favorite AR-15 build, a compact and mobile SBR emphasizing both aesthetics and functionality. The build features a Daniel Defense upper receiver known for reliability, paired with traditional A2 sights and modern accessories like a vertical foregrip and red dot optic. Live-fire demonstrations highlight its performance and manageable recoil.

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 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 video demonstrates the installation of a Kynshot Hydraulic Buffer (RB5000) into an AR-15 platform. The presenter shows the disassembly process, highlighting the removal of the standard carbine buffer and recoil spring. The Kynshot buffer is then installed, and the firearm is reassembled and function-checked, emphasizing its role in reducing felt recoil and bolt bounce.

This review focuses on the Radian Raptor SD-SL, a gas-busting charging handle designed to mitigate gas blowback, especially when using suppressed fire on AR-15 platforms. The video demonstrates its installation and highlights its ambidextrous latches and ported shaft for gas redirection. It's presented as a high-quality aftermarket upgrade for improved shooting experience.

This video compares the audible difference between a standard AR-15 buffer spring and the Armaspec Stealth Recoil Spring (SRS). It highlights the 'twang' noise of traditional springs during charging handle operation and demonstrates how the SRS provides a significantly smoother and quieter experience. The installation process is shown to be simple, replacing the two-piece buffer and spring with a single, captured unit.

This video demonstrates the difference between a standard AR-15 buffer spring and an upgraded Sprinco Chrome Silicon spring. The Sprinco spring is shown to provide a smoother and quieter cycling action after installation. The comparison highlights the visual differences and the audible/tactile improvements in firearm operation.