American Precision Firearms Gen 4 Fat Bastard Muzzle Brake, Steel, 6mm

The American Precision Firearms Gen 4 Fat Bastard Muzzle Brake in 6mm (brand part no. G4F5860S) is a self-timing steel brake threaded 5/8×24 and built for shooters who want flat, controllable recoil on a precision or competition rifle. American Precision Firearms designed the Gen 4 line around calibrated, tunable top ports that were tested for size, location, and gas flow to virtually eliminate vertical muzzle movement, so follow-up shots stay on target faster. The self-timing design means it indexes correctly on installation without shims or extra fitting work.

Key Specifications

• Bored for 6mm projectiles, matching the brake to the caliber for optimal gas redirection.
• Threaded 5/8×24, a common precision rifle thread pitch.
• Machined from steel for durability under sustained firing.
• Features self-timing installation, so the brake indexes correctly without shims.
• Uses tunable top ports, calibrated for maximum vertical recoil control.
• Measures 3.30 inches overall length and 1.10 inches in diameter, a compact footprint for most builds.

Frequently Asked Questions

What caliber is this brake designed for? It is bored for 6mm projectiles.

Do I need to shim it during installation? No, the self-timing design is built to index correctly without shims.

Buy the American Precision Firearms Gen 4 Fat Bastard Muzzle Brake

Precision rifle shooters chasing flatter recoil and faster follow-up shots will get real value from the Gen 4’s tunable port design, engineered specifically to cut vertical muzzle rise. Order it through our Lubbock, Texas gun shop and browse more AR muzzle devices from American Precision Firearms and other top brands.