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Obsidian Arms 3 Gun Thunder Brake Compensator .223/5.56mm Review

Posted by Mandu Moses on Jun 21st 2024

I recently had the opportunity to test the Obsidian Arms 3 Gun Thunder Brake Compensator designed for rifles chambered in .223/5.56mm. This muzzle brake is specifically designed for ½ - 28 TPI thread devices and features large side ports and smaller top ports to help maintain rifle accuracy.

Obsidian Arms 3 Gun Thunder Brake Compensator .223+5.56mm

Where to Buy

The Obsidian Arms 223/556 Thunder Brake is available for purchase at the following websites:

First Impressions

Upon receiving the Thunder Brake, it came in basic packaging—a plastic bag with a cardboard header card displaying the Obsidian Arms logo and contact details. The package included the brake itself and a crush washer for installation. The product proudly declares its origin with a "Made in Minnesota, USA" label.

Installation & Setup

Installing the Thunder Brake is a straightforward process. Here’s how to do it:

Initial Preparation

Begin by safely clearing your rifle and removing any existing muzzle device, if present. This step is crucial to ensure a clean starting point for the installation of the Thunder Brake.


Once the previous muzzle device is removed, take the Thunder Brake and gently thread it onto the rifle’s barrel. Rotate it by hand until it feels snug against the barrel’s end. This hand-tightening ensures that the brake is seated properly without cross-threading.

Obsidian Arms 3 Gun Thunder Brake Compensator .223+5.56mm 2

Wrench Tightening and Timing

After hand-tightening, use a wrench to secure the brake further. This is where precision comes into play. The timing, or alignment, of the brake is essential for its optimal function. The brake must be aligned so that its horizontal and vertical axes match those of the barrel. This alignment guarantees that the brake’s ports will operate as intended upon firing.


While the basic installation is straightforward, there is room for customization. You have the option to fine-tune the compensator to suit their individual shooting styles. This involves adjusting the brake’s position to achieve the desired balance between recoil reduction and muzzle control.

Specifications of the Obsidian Arms 3 Gun Thunder Brake Compensator

Here is a list of the Obsidian Arms 3 Gun Thunder Brake Compensator specs:

  • Caliber Compatibility: .223/5.56mm
  • Thread Pattern: 1/2x28 TPI (standard for AR-15 barrels)
  • Length: Approximately 2-3 inches
  • Diameter: Approximately 1 inch
  • Material: Steel
  • Weight: 4.4oz
  • Finish: Black Oxide
  • Port Design: Two large ports on each side and several smaller ports on top.

Field Test Results

My initial observations with the Obsidian Arms Thunder Brake yielded inconclusive results. When I first tested it using a Viridian RFX 45 closed reticle optic at closer distances, I didn't perceive a significant difference in the point of impact. However, after re-zeroing the rifle with a Black Hound scope, the Thunder Brake's influence became undeniable.

The shift in point of impact itself confirmed that the brake was indeed affecting the rifle's handling. The true nature of this effect became evident as I progressively increased the firing distance after re-zeroing.

Obsidian Arms 3 Gun Thunder Brake Compensator .223+5.56mm

The large ports on either side of the Thunder Brake played a crucial role in controlling muzzle flips along the vertical axis. I was initially skeptical about the efficacy of the smaller top ports in managing vertical rise. However, to my surprise, even at 300 yards, they effectively mitigated vertical movement, allowing me to place multiple rounds precisely on target.

Unfortunately, the range I was at didn't have a 400-yard gong to push the test further. Nevertheless, the improvement at 300 yards was undeniable. Follow-up shots were significantly faster, reacquiring the target after firing was quicker, and spotting bullet impacts was much easier.

For comparison, with my previous muzzle brake from White Lable Armory, the rifle would be back on target around the same time the bullet struck the target at 300 yards. In contrast, the Obsidian Arms Thunder Brake provided a noticeable window of a quarter to half a second between firing and bullet impact visibility. This clearly demonstrates the substantial reduction in muzzle flip and the resulting improvement in on-target accuracy after pulling the trigger.

Essentially, the initial lack of a noticeable change at close range transformed into a revelation of the Thunder Brake's effectiveness at longer distances. The brake's design, with its combination of strategically placed ports, demonstrably enhanced controllability and precision, especially at extended ranges.


Several features of the Obsidian Arms 223/556 Thunder Brake stood out:

  • Large Flats for Easy Installation: The flats on the top and bottom of the brake provide ample surface area for wrench installation using a variety of tools like a monkey wrench, crescent wrench, or armorer's wrench.
  • Durable Finish: The black oxide finish matched my rifle nicely and was resistant to wear.
  • Excellent Performance: The Thunder Brake effectively reduced muzzle flip and improved controllability, especially at distance.
  • Easy to Time: The straightforward design facilitated proper alignment with the barrel.
  • Directed Noise Mitigation: The concussion of the rifle blast was noticeably lower for the operator.

While the performance was impressive, there were some minor cosmetic issues:

  • Visible Machine Marks: Some machine marks were visible on either side of the ports.
  • Exposed Threading: The threading slightly extended past the base of the first port.

Final Thoughts

Obsidian Arms 3 Gun Thunder Brake Compensator .223+5.56mm

The Obsidian Arms 223/556 Thunder Brake excels in optimizing .223/5.56 caliber firearms. Its large side ports effectively reduce muzzle flash, while the smaller top ports help control muzzle rise. Installation is straightforward, and the performance is superb, making it one of the best muzzle brakes I have tested to date.