Bushmaster M4 Patrolman’s Upper | 5.56 NATO | 0040008BLK

This is a Bushmaster M4 Patrolman’s complete upper receiver assembly configured for AR-15 platforms and chambered in .223 Rem / 5.56 NATO. It is a flat-top, forged 7075 A4 receiver built with a carbine-length gas system and salt-bath nitride bolt carrier group with an MPI-tested bolt. Standard A2-style handguard and A2 birdcage flash hider are fitted and a flip-up rear sight is included.

Designed as a direct-fit upper for AR-15 lower receivers, the assembly suits applications such as target/precision shooting and varmint/hunting configurations where a reliable, serviceable upper is required. Note that some core dimensional details are listed inconsistently across source materials; please review the product specifications below.

Product Specifications

• The caliber is listed as .223 REM / 5.56 NATO in source materials.
• The barrel length is reported as 16″ and 20″ across different listings.
• The rate of twist is reported as 1:7 and 1-in-9 across different listings.
• The barrel finish/type is listed as Black and the barrel treatment as Salt Bath Nitride.
• The handguard is listed as an M4 Double Head Shield style with a Black finish.
• The receiver is a Flat Top 7075 Forged A4 design.
• The gas system is a Carbine length configuration.
• The bolt carrier group is a Salt Bath Nitride (SBN) BCG with an MPI-tested bolt reported in source materials.
• The sights are listed as A2 front with a flip-up rear sight.
• The muzzle device is an A2 birdcage flash hider with a 1/2×28 thread pattern.
• The unit is specified to fit AR-15 platforms.
• The finish color is listed as Black.
• The manufacturer part number is 0040008BLK.
• The UPC is 604206200259.

This Bushmaster M4 Patrolman’s upper combines forged receiver construction, a nitrided BCG, and standard A2 furniture to deliver a serviceable, maintenance-friendly assembly for AR-15 users who value parts compatibility and proven manufacturing methods. Its flat-top receiver offers optics mounting flexibility while the included sights and A2 handguard preserve a traditional stout profile.