Stern .45 ACP barrels are the perfect choice for firearm enthusiasts looking to create a custom, dedicated .45 ACP AR-15 upper group. Expertly machined to exacting tolerances, these barrels are designed with an uncompromising focus on quality, ensuring exceptional performance and reliability. Whether for tactical applications, competitive shooting or personal builds, the SD .45 ACP barrel provides the durability and precision needed to enhance accuracy and consistency. Built for shooters who demand excellence, this barrel is a dependable foundation for any high-performance AR-15 configuration. Barrel length is measured in overall length from breech to muzzle, providing clarity for users when selecting or fitting barrels to their firearm This barrel is threaded 0.578-28 4150 chrome-moly steel, known for its toughness and resistance to wear and tear, ensuring long lasting performance 1:16 inches twist, suitable for lighter, smaller projectiles, enhancing accuracy and efficiency Melonite coating, enhancing the surface hardness and corrosion-resistance of metal components Barrel comes with locating pin installed, simplifying installation and ensuring precise alignment for consistent performance