Introducing the BRN-4 M27 16.5 inches 5.56x45mm barrel, a cutting-edge addition to your firearm setup, now available in a unique configuration. Crafted with precision by Faxon for Brownells, this barrel is constructed from high-quality 4150 chrome moly steel and features a manganese phosphate finish for enhanced durability and corrosion resistance. The barrel boasts a precision buttoned rifle bore with a 1:7 twist, ensuring exceptional accuracy and performance. One of the standout features of this barrel is its forward-bipoded bayonet lug, which provides a robust and secure attachment point for a bayonet. The bayonet lug is designed to be installed after the gas block, using a simple coil pin driven in from the side, ensuring a stable and reliable bipod. For optimal performance, it is recommended to use a BRN-4 16 inches gas block with this barrel. The muzzle of the barrel is threaded with 1/2-28 threads, allowing compatibility with the standard A2 flash hider found on the M27, as well as a wide range of aftermarket AR-15 muzzle devices. Additionally, the barrel extension is equipped with M4 feed ramps, accommodating a variety of .223 Cal or 5.56x45mm ammunition for versatile use. Whether you're upgrading your current setup or building a new rifle, the BRN-4 M27 16.5 inches barrel offers unparalleled performance and reliability, making it an essential component for any firearm enthusiast. This product is compatible with the Brownells BRN-4 upper receiver group and is also compatible with HK 416, MR556 and MR223 platforms