The Brownells BRN-4 M27 barrel features a 16.5-inch chrome lined bore chambered in 5.56x45mm NATO with a durable phosphate finish for enhanced corrosion resistance.BRN-4 M27 5.56x45mm NATO barrel16.5-inch length with medium profileChrome lined bore for extended barrel lifePhosphate finish for corrosion protectionCompatible with M27 rifle buildsEngineered for reliable performance and durability this barrel is ideal for tactical applications and precision shooting where consistent accuracy and longevity are essential.