ABC RIFLE COMPANY AR-15 6in Custom Ported Barrel Extender Muzzle Brake 1/2x28 Matte Black. The extended length makes it ideal for pin-and-weld applications and the pre-drilled hole simplifies permanent attachment to bring shorter barrels to legal length. Its threaded in 1/2x28in compatible with AR-15 platforms chambered in 5.56 NATO or .223 Remington. Wrench flats ensure easy installation. This brake is perfect for builders seeking both functional performance and NFA compliance. Specifications for ABC RIFLE COMPANY AR-15 6in Custom Ported Barrel Extender Muzzle Brake: Manufacturer: ABC RIFLE COMPANY Color: Black Caliber: 5.56x45mm NATO .223 Remington Finish: Matte Fabric/Material: 6061-T6 Aluminum Threads per Inch: 1/2x28 Gun Make: AR Platform Gun Model: AR-15 Outer Diameter: 1 in Length: 6 in Weight: 5 oz Gun Type: Rifle Package Contents: ABC RIFLE COMPANY AR-15 6in Custom Ported Barrel Extender Muzzle Brake What firearm models does the manufacturer say ABC RIFLE COMPANY AR-15 6in Custom Ported Barrel Extender Muzzle Brake is compatible with? The manufacturer suggests that ABC RIFLE COMPANY AR-15 6in Custom Ported Barrel Extender Muzzle Brake is compatible with AR-15ABC RIFLE COMPANY MB15-3CUT: AR-15 6in Custom Ported Barrel Extender Muzzle Brake 1/2x28 Matte Black