KAC Sandcutter Carrier - Physical & Gas Key Swap

This video announces a new service from School of the American Rifle offering physical inspections and 'autopsies' for AR-15 style bolt carrier groups (BCGs). For a fee of $40 labor plus shipping and processing costs, customers can send in their BCGs to be assessed for proper function, protrusion, and headspace, receiving a detailed health report. The service is limited to AR-15 platforms and requires specific payment and packaging instructions.

This video provides a detailed physical inspection of a Knight's Armament Sandcutter Bolt Carrier Group (BCG). It covers essential checks like bolt protrusion, extractor function, headspace, and gas ring integrity using various gauges. The instructor also performs a reverse torque test on the carrier key screws and identifies minor gas leakage, leading to a recommendation for carrier key replacement and proper staking.

This video details a gunsmithing fix for Ruger AR-556 rifles experiencing bolt carrier key clearance issues. The instructor demonstrates how to modify the receiver extension (buffer tube) by filing a notch and smoothing the face to allow the buffer retainer to function correctly while gaining an extra rotation. This modification increases the critical gap between the bolt carrier key and the lower receiver, preventing potential damage.

This video provides a detailed autopsy of a Knights Armament Sandcutter AR Bolt Carrier Group (BCG) that was causing reliability issues. The instructor systematically disassembles and inspects each component, including the bolt, extractor, firing pin, cam pin, and carrier bore, using various gauges and tools to identify potential problems. The primary finding is a broken gas key fastener, which is identified as the cause of gas leakage and the firearm's failure to cycle.

This video provides an in-depth physical inspection and testing of five Knight's Armament Company (KAC) bolt carrier groups (BCGs) and one Lewis Machine & Tool (LMT) Enhanced Bolt. The instructor meticulously gauges various dimensions, checks for wear, and assesses the internal finishes of the carriers. The process includes replacing carrier keys and screws, performing torque tests, and highlighting the unique features of the LMT Enhanced Bolt, offering valuable insights for AR-15 owners and gunsmiths.

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.