Switching Barrels on Your AR 15 Upper: A How-To

Switching barrels on your AR-15 upper receiver can be a useful skill for customizing your rifle to meet different shooting needs or replacing a worn-out barrel. Here’s a step-by-step guide on how to switch barrels on your AR-15 upper receiver:

1. Gather Necessary Tools and Equipment:

  • Barrel vise block or upper receiver vise block.
  • Armorer’s wrench.
  • Torque wrench.
  • Barrel nut wrench (if your new barrel requires it).
  • Roll pin punches and starter punch.
  • Bench vise.
  • Barrel nut grease or aeroshell grease.
  • AR Uppers receiver assembly lube.
  • Cleaning supplies.
  • Eye protection.

2. Ensure Safety:

  • Always wear eye protection during the process to protect your eyes from debris and small parts.

3. Clear the Firearm:

  • Remove the upper receiver from your AR-15 lower and ensure it’s unloaded.

4. Remove Handguard:

  • If your handguard is attached to the barrel nut, remove it using the appropriate tools.

5. Secure Upper Receiver:

  • Place your upper receiver securely in a barrel vise block or upper receiver vise block.

6. Remove the Gas Block and Gas Tube:

  • Use a roll pin punch to remove the gas block’s pins.
  • Carefully slide the gas block and gas tube off the barrel.

7. Remove Muzzle Device:

  • If your muzzle device is attached to the barrel, use the appropriate wrench to remove it.

8. Loosen Barrel Nut:

  • Using an armorer’s wrench, apply controlled force to loosen the barrel nut. Make a note of the number of rotations it takes to remove the barrel nut for reassembly.

9. Remove the Barrel:

  • Carefully slide the old barrel out of the upper receiver.

10. Install the New Barrel: – Apply a small amount of barrel nut grease or aeroshell grease to the threads of the barrel extension. – Slide the new barrel into the upper receiver, ensuring that the gas tube hole lines up with the gas port on the barrel.

11. Torque the Barrel Nut: – Secure the upper receiver in a bench vise or upper receiver vise clamp. – Using the appropriate barrel nut wrench and torque wrench, tighten the barrel nut to the manufacturer’s recommended torque specification. This is typically around 30-80 ft-lbs, but it varies based on the type of barrel and barrel nut you’re using. – Verify that the gas tube hole remains aligned with the gas port in the barrel.

12. Reinstall Gas Block and Gas Tube: – Slide the gas tube through the gas port in the barrel and into the gas key on the bolt carrier group (BCG). – Slide the gas block onto the barrel and secure it in place with the provided screws or pins. – Ensure the gas tube lines up with the gas port on the gas block.

13. Reattach Muzzle Device: – If your muzzle device was removed, thread it back onto the barrel and secure it using the appropriate wrench.

14. Reattach Handguard: – If your handguard was removed, reattach it as per the manufacturer’s instructions.

15. Inspect and Lubricate: – Inspect all components for proper alignment and functionality. – Apply a light coat of upper receiver assembly lube to key contact points.

16. Final Check and Function Test: – Perform a function test to ensure your upper receiver operates correctly. Check the safety, trigger, bolt catch, and magazine release.

Once you have successfully switched barrels on your AR-15 upper, reassemble it with your lower receiver, and perform a function check to ensure everything is in working order. If you’re not comfortable with this process, it’s advisable to seek assistance from a qualified gunsmith or experienced AR-15 builder.

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