Stern Defense MOD4 16.1″ 9mm Upper, 15″ M-LOK

The Stern Defense MOD4 is a complete 9mm AR-style upper assembled around a 16.1-inch Melonite steel barrel and paired with a 15-inch M-LOK handguard. It includes a Glock-cut SD BU9 bolt, SD CH1 enhanced charging handle, dust cover, and forward assist. The barrel is threaded .5-36 with a 1:10" twist rate and the receiver is finished in anodized 7075-T6 aluminum.

Key Specifications

• Caliber: 9mm.
• Barrel length: 16.1 inches.
• Barrel material: Steel.
• Barrel finish: Melonite.
• Rate of twist: 1:10".
• Threading: .5-36.
• Handguard: 15-inch M-LOK.
• Bolt: SD BU9 Glock-cut.
• Charging handle: SD CH1 enhanced.
• Receiver material/finish: 7075-T6 aluminum, anodized.

Built to provide a durable, factory-assembled foundation for range use, conversion projects, or competition setups, the MOD4 upper combines serviceable materials and practical features in a package ready for Glock-cut lowers or standardized adapters. Its Melonite-treated barrel and M-LOK handguard offer corrosion resistance and modularity for accessories, making it a straightforward option for builders who prioritize consistent performance and reliable components.