The Perpetual Agony of the AR-9

Published on November 4, 2021
Duration: 6:33

This guide details how to troubleshoot reliability issues in AR-9 platforms, specifically focusing on magazine feed lip interference with the last round bolt hold open (LRBHO) lever. It involves comparing magazine dimensions using digital calipers to identify the cause of malfunctions, particularly when using ASC or C-Products magazines. The analysis helps determine if a different magazine brand or potential modification is needed for consistent performance.

Chapters

  1. 00:00Introduction and Previous Configuration
  2. 01:12The Upgrade Process
  3. 02:08Shooting Performance
  4. 02:44Magazine Reliability Deep Dive
  5. 04:18Technical Analysis of Feed Lips
  6. 06:10Conclusion and Future Plans

Frequently Asked Questions

What causes reliability issues in AR-9 firearms with certain magazines?

Reliability issues in AR-9s, particularly with ASC and C-Products magazines, often stem from the last round bolt hold open (LRBHO) lever interfering with the top round. This interference is caused by the feed lip geometry of the magazines being slightly too high, preventing smooth cycling.

How can I diagnose magazine feed lip interference in my AR-9?

To diagnose feed lip interference, compare your problematic 9mm magazines side-by-side with known reliable ones like Metalform. Use digital calipers to measure the distance from the magazine catch to the feed lips; a difference of approximately 0.025 inches (1.20" vs 1.175") can indicate the issue.

More Gunsmithing & DIY Videos You Might Like

More from Hop

View all →