Smyth Busters: Large-Caliber ARs Need Heavy Hammer Springs?

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 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 guide, presented by an expert firearms instructor, details the benefits and installation of adjustable triggers for platforms like the AR-15. It covers understanding trigger mechanics, adjusting pull weight, reset, and overtravel, and highlights ideal users for these components. The instruction emphasizes safety and practical application for competition and precision shooting.

This guide, presented by School of the American Rifle, details how to identify and replace a malformed weld spring in an AR-15 Delta Ring assembly. A misaligned weld spring can cause the gas tube to be pushed off-center, leading to excessive friction or damage to the carrier key and gas tube. Replacing the faulty component ensures proper gas tube alignment and firearm reliability.

This YouTube video focuses on a "300 Blackout Borderlands Build," suggesting a custom firearm project inspired by the popular video game series. The title indicates a specific caliber, 300 Blackout, and a potential emphasis on customization or a unique aesthetic. The content likely involves assembling or showcasing a firearm with characteristics that evoke the Borderlands universe, potentially including unique paint schemes, modifications, or accessories.

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 details the installation of a Geissele MK8 Super Modular Rail on an AR-15. Key steps include using a Geissele Reaction Rod for upper receiver stability, proper torquing of the proprietary barrel nut, and secure installation of the gas block and tube. The rail is then slid on and secured with two cross-bolts using a T-handle hex wrench. Final steps involve muzzle device installation and a thorough inspection.

Proper ammunition storage is crucial for maintaining reliability and safety. Avoid storing ammo in cardboard boxes in damp environments, as this leads to moisture absorption and corrosion. Utilize airtight containers like ammo cans and control humidity with desiccants like silica gel packs. Heat accelerates gunpowder and primer degradation, so store ammo at stable room temperatures. Reloading primers are particularly vulnerable to moisture and require strict airtight storage.

This video demonstrates how to upgrade an AR-15's A2 furniture to Magpul components. It details the removal of the A2 grip using a Bondhus hex set and the installation of a Magpul MIAD grip with interchangeable backstraps for improved ergonomics. The process also covers preparing and installing the Magpul PRS stock, highlighting its adjustable features for cheek weld and length of pull.

This video explores the custom Remington 11-87 shotgun used as a prop in 'No Country for Old Men.' The film required a semi-automatic shotgun with a suppressor, a combination not readily available at the time. Prop master Larry Zanoff details how a non-functional, 'homemade' looking suppressor was custom-built for the 11-87, with the iconic silenced sound effect achieved entirely in post-production.