The Bushmaster 0040008BLK M4 Patrolman’s Upper 5.56x45mm NATO pairs a classic carbine-style profile with a complete, ready-to-pin upper receiver for your AR-15. Built around a flat-top upper with integrated flip-up rear sight and a fixed front sight base, this assembly delivers a dependable sight picture and a familiar M4-style handling experience. The 16-inch barrel is chambered in 5.56x45mm NATO and designed to balance maneuverability with practical accuracy for a wide range of shooting needs.

This complete upper receiver is ideal for shooters looking to upgrade an existing AR-15 or finish a new build with a proven Bushmaster configuration. The carbine-length gas system and lightweight design make it well suited for range sessions, training, and general-purpose use. With Bushmaster’s long-standing reputation for reliable AR-platform components, this M4 Patrolman’s upper offers a straightforward path to a dependable, no-nonsense rifle setup.

• Manufacturer: Bushmaster
• Model: M4 Patrolman’s Upper 0040008BLK
• Caliber: 5.56x45mm NATO
• Barrel Length: 16"
• Receiver Type: Complete upper assembly
• Handguard Finish: Black
• Gas System: Carbine length