Manufactured in the US with the highest quality components, the BRN-15 Upper Receiver Groups are great starts for your next build. Pick your preferred bolt carrier group and charging handle to complete. The BRN-15 Upper Receiver Groups feature a 5.56x45mm NATO chambered, nitride finished barrel, available in several popular lengths. Models are available in a Government, medium profile barrel, with the 16 inch also available in a lightweight contour. Barrels feature a gas block dimple, that the rear gas block screw securely engages. All barrels are stress releived. Unique MLOK handguard extends past the gas block, to provide as much usable real estate as possible. Anti-rotation t Mfg: Brownells