Product Description The Stern Defense .45 ACP 10.5-inch barrel is built for AR-15 style pistol-caliber builds, featuring durable 4150 chrome-moly steel with a black Melonite finish for enhanced wear and corrosion resistance. This barrel is threaded for common .45 ACP muzzle devices and is designed to deliver reliable performance with the correct buffer and upper receiver configuration. Product Highlights 10.5-inch .45 ACP barrel for AR-15 platform pistol-caliber builds 4150 chrome-moly steel construction for strength and longevity Black Melonite coating for improved corrosion and abrasion resistance Threaded muzzle (0.578-28) for compatibility with many .45 ACP muzzle devices 1:16 twist rate optimized for common .45 ACP projectile weights Specs Brand: Stern Defense Manufacturer Part Number: 00645ACPBARREL105INCHD UPC: 850001176378 Caliber: .45 ACP Barrel Length: 10.50 in Material: 4150 chrome-moly steel Finish/Coating: Black Melonite Muzzle Threads: 0.578-28 Twist Rate: 1:16 Country of Manufacture: Made in the USA Compatibility Note: Must be used with an 11 oz buffer or heavier when using a carbine spring; .45 ACP uppers require an enlarged ejection port Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&&';;s manufacturer.