The Stern Defense STERN DEF. PISTOL UPPER 9MM delivers a complete AR-15 SD MOD 5 9MM upper receiver assembly with M-LOK compatibility, engineered for reliable performance in a pistol-caliber platform. This 9mm Luger upper features a 6-inch steel barrel finished in Melonite for enhanced hardness and corrosion resistance, paired with a proven 1:10 twist to stabilize a wide range of 9mm ammunition. Made in the USA, this upper is designed to integrate seamlessly with standard AR-15 lowers, offering a clean, modular solution for users seeking enhanced versatility in competition, plinking, or defensive applications. Its compact dimensionsapproximately 4.00 x 3.90 x 28.25 inches when assembled with compatible componentsmaximize balance and control, while the M-LOK compatibility provides flexible accessory mounting for sights, lights, and grips. Whether upgrading an existing rifle or building a dedicated 9mm pistol platform, the Stern Defense upper delivers consistent cycling, precision alignment, and durable construction to meet demanding field conditions. This 9mm upper receiver assembly is a robust choice for shooters prioritizing reliability, compatibility, and American-made quality in a compact, ready-to-run package.