HM Defense MonoBloc Upper .223/5.56 16″ 15″ M-LOK

The HM Defense MonoBloc Upper is a complete AR-15 upper assembly built for match-grade performance and consistent operation. It features a 16″ HM, 4150 Chrome Moly match-grade barrel with an integral machined patented gas block and a carbine gas system. The assembly includes a 15″ free-float M-LOK handguard and a 7075-T6 aluminum receiver finished in black anodize, providing a rigid, lightweight platform for optics and accessories. Mil-Spec components, a patented HMB bolt, and an optic-ready configuration complete the package.

Key Specifications

• The caliber is .223 Rem / 5.56x45mm NATO.
• The barrel length is 16″.
• The barrel is 4150 Chrome Moly match grade, tripled honed and button rifled.
• The barrel finish is Black Cerakote.
• The twist rate is 1:8″.
• The handguard is a 15″ M-LOK free-float design machined from 6061-T6 aluminum.
• The receiver is 7075-T6 aluminum with a black anodized finish.
• The gas system is a carbine gas system with an integral machined patented gas block.
• The bolt is a patented HMB bolt.
• The upper is optic ready and includes Mil-Spec components, a charging handle, and a dust cover with an American flag.

Designed to serve as a durable, match-capable upgrade for an AR-15 platform, this MonoBloc upper pairs precise barrel work with a rigid free-floating handguard and trusted Mil-Spec components to deliver reliable performance across target, competition, and field applications. Its configuration supports optics and modern accessory layouts while prioritizing consistency and build quality.