Building an 8.6 Blackout AR

Published on September 19, 2025
Duration: 27:43

This video provides a step-by-step guide to building an 8.6 Blackout AR-15 upper receiver. It details the installation of key components including the barrel, handguard, gas block, muzzle device, charging handle, and bolt carrier group. The presenter emphasizes proper torque specifications and alignment for critical parts, offering practical tips throughout the build process.

Quick Summary

The 8.6 Blackout cartridge is designed for large-frame AR platforms, serving as the equivalent of 300 Blackout for AR-15s. It uses a .338 projectile in a shortened 6.5 Creedmoor case, making it an excellent subsonic cartridge for suppressed shooting and effective for hunting, particularly hogs.

Chapters

  1. 00:10Introduction to 8.6 Blackout
  2. 00:31Parts Overview: Lower Receiver
  3. 01:34Parts Overview: Upper Receiver & Handguard
  4. 03:10Optic and Barrel Selection
  5. 03:59Suppressor and Muzzle Device
  6. 04:28Charging Handle and Arca Rail
  7. 05:31Gas Block and Tools
  8. 05:43Upper Receiver Vice Block Setup
  9. 06:00Barrel Installation
  10. 06:46Barrel Nut Installation
  11. 07:59Gas Tube and Gas Block Installation
  12. 08:48Handguard Alignment Check
  13. 10:32Handguard Fitment and Installation
  14. 11:15Handguard Mounting Screws
  15. 13:18Muzzle Device Installation
  16. 17:12Optic Mounting
  17. 18:09Suppressor Fit Check
  18. 19:01Arca Rail Installation
  19. 20:03M-LOK Accessory Mounting
  20. 21:16Troubleshooting M-LOK Mounting
  21. 23:45Charging Handle and Bolt Carrier Group Installation
  22. 25:17Upper and Lower Receiver Assembly
  23. 25:53Action Cycling and Suppressor Re-attachment
  24. 26:25Final Build Overview
  25. 26:46Upcoming Videos: Handloading & Shooting

Frequently Asked Questions

What is the purpose of the 8.6 Blackout cartridge?

The 8.6 Blackout is designed for large-frame AR platforms, serving as the equivalent of 300 Blackout for AR-15s. It uses a .338 projectile in a shortened 6.5 Creedmoor case, making it an excellent subsonic cartridge for suppressed shooting and effective for hunting, particularly hogs.

What are the key components used in building this 8.6 Blackout AR upper receiver?

The build features an Aero Precision upper receiver, a Faxon 16-inch 8.6 Blackout barrel with a 1:3 twist rate, a Midwest Industries Combat HD handguard, a Dead Air Nomad-30 suppressor, and a Strike Industries Arca rail for accessory mounting.

What is the recommended torque specification for the barrel nut on an AR platform?

For this build, the presenter recommends torquing the barrel nut to anywhere between 50 to 60 foot-pounds. This ensures a secure fit and proper alignment of the barrel and handguard assembly.

Why is dimpling the barrel for the gas block recommended?

Dimpling the barrel for the gas block set screws provides a more secure and consistent seating for the gas block, preventing it from shifting under recoil. This is especially important for preventing gas leaks and ensuring reliable function, particularly with rapid fire.

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