Phase 5 Weapon Systems FATMAN556 FATman Hex Brake Black Parkerized Steel with 1/2"-28 tpi Threads & 3" OAL for 223 Rem, 5.56x45mm NATO AR-Platform

The Phase 5 Weapon Systems FATMAN556 Hex Brake is a precision muzzle brake engineered for AR-platform rifles in .223 Remington and 5.56 NATO. Built for shooters who demand flat recoil control and shot-to-shot consistency—whether you're dialing in a precision build, running competition stages, or pushing accuracy downrange—this brake combines serious performance with the custom-shop aesthetics that discerning gun builders demand.

The FATMAN design centers on two large, ventilated baffle sections that work together to manage recoil and compensate for muzzle rise. The top ports are machined at a 20-degree forward angle, directing expelled gas in a way that promotes repeatable, flat shooting behavior. This geometry keeps your sight picture stable shot after shot, a critical advantage when precision matters. The brake is engineered so its first chamber wall sits as close to the barrel crown as possible, preserving your barrel's inherent accuracy and minimizing any point-of-aim shift from the muzzle device itself.

Finished in mil-spec black parkerized steel, the FATMAN wears the iconic Phase 5 hex profile—a hallmark of quality custom builds. It threads on 1/2"-28 (standard for modern 5.56 uppers) and includes a crush washer for reliable installation. At 3 inches overall length, it's substantial enough to deliver real compensation without overhanging most handguards.

Key Features

• Two large ventilated baffles for effective recoil reduction and shot-to-shot consistency
• 20-degree forward-angled top ports direct gas for flat performance
• Optimized chamber design preserves barrel accuracy and zero stability
• Iconic Phase 5 hex profile for custom builder aesthetics
• Mil-spec black parkerized finish for durability and corrosion resistance
• Includes crush washer for installation

Specifications

Frequently Asked Questions

Will this fit my AR-15 upper?

Yes, the FATMAN556 threads on 1/2"-28, the standard thread pitch for modern .223/5.56 uppers. It will fit any AR-platform rifle with a 1/2"-28 barrel.

What calibers does this brake work with?

The FATMAN556 is designed for .223 Remington and 5.56 NATO ammunition fired from compatible AR-platform barrels with 1/2"-28 threading.

What's included in the box?

The FATMAN556 comes with one crush washer for installation. A gunsmith or armorer can install it for you, or you can do it yourself if you have the proper tools and knowledge of crush washer installation.

How does this brake affect accuracy?

The design was engineered so the first chamber sits as close to the barrel crown as possible, helping preserve the barrel's accuracy and minimize zero shift caused by the muzzle device.