HM Defense MonoBloc Upper – 5.56 NATO / .223 Rem – 16" Black Cerakote Barrel – 7075-T6 Aluminum Black Anodized Receiver – 15" M-LOK Free-Float Handguard – Model 16MBUP556L
UPC: 854164007234
Upgrade your AR-15 rifle with cutting-edge engineering and unmatched durability using the HM Defense MonoBloc Upper, one of the most advanced and reliable uppers available on the market. Built around HM Defense’s patented MonoBloc Barrel System, this 16" upper offers enhanced accuracy, superior gas system integrity, and exceptional reliability for tactical training, competition shooting, and home defense setups.
Chambered in 5.56x45mm NATO / .223 Remington, this upper delivers outstanding versatility and compatibility for all AR-15 platforms. The precision-machined 7075-T6 aluminum receiver features a rugged black anodized finish, while the Black Cerakote-treated MonoBloc barrel offers superior heat resistance, corrosion protection, and long-term durability under high rates of fire. Paired with a 15" M-LOK free-float handguard equipped with an extended top rail for optics and accessories, this upper provides the perfect balance of lightweight construction, accuracy, and modularity.
Patented 16" MonoBloc Barrel – Unmatched Reliability & Precision
HM Defense sets itself apart with its MonoBloc Barrel System, a revolutionary design where the gas block is integrally machined into the barrel itself.
MonoBloc Advantages:
Eliminates traditional gas block pinning and alignment issues
Improves accuracy through reduced barrel stress
Enhances gas system integrity and reliability
Reduces potential failure points under rapid or sustained fire
Provides superior consistency and shot-to-shot performance
A premium innovation engineered for shooters who demand true long-term reliability.
5.56 NATO / .223 Rem Chambering for Maximum Versatility
The upper is chambered for both 5.56 NATO and .223 Remington, allowing shooters to choose between widely available ammunition types.
Caliber Benefits:
Compatible with all AR-15 lower receivers
Ideal for tactical training, defense, and competition
Supports a wide variety of bullet weights and loads
Offers excellent ballistic performance and low recoil
A flexible upper for any shooting application.
Black Cerakote Barrel – Superior Heat & Corrosion Resistance
The 16" MonoBloc barrel is protected by a durable Black Cerakote finish, ensuring long-lasting performance even in the harshest environments.
Cerakote Advantages:
Heat-resistant for high-volume shooting
Superior corrosion protection
Reduced friction and wear
Tactical low-glare appearance
Built for rugged use in the field, at the range, or during training.
7075-T6 Aluminum Upper Receiver – Strength You Can Trust
Featuring a high-strength 7075-T6 forged aluminum receiver, this upper maximizes durability without adding unnecessary weight.
Receiver Features:
Hard black anodized for wear resistance
Lightweight yet extremely strong
Precision machined for tight tolerances
Ensures compatibility with standard AR-15 lowers
A premium foundation for your rifle build.
15" M-LOK Free-Float Handguard with Extended Rail
The included 15-inch M-LOK free-float handguard enhances accuracy while offering maximum mounting flexibility for optics and accessories.
Handguard Highlights:
Free-float design prevents barrel contact for improved precision
M-LOK slots for attaching lights, grips, bipods, and more
Full-length top rail allows red dot, scope, and iron sight combinations
Slim, ergonomic profile for comfortable handling
Perfect for customizing your rifle to your mission or shooting style.
Optimized for AR-15 Platforms
This upper is a drop-in, ready-to-use upgrade for any mil-spec AR-15 lower receiver.
Compatibility Benefits:
Works with standard AR-15 buffers, stocks, and triggers
Ideal for new builds, upgrades, or replacements
Reliable performance across all lower brands
No special tools required for installation
A seamless upgrade for any AR enthusiast.
Engineered for Accuracy, Durability & High Performance
Every component of the HM Defense MonoBloc Upper is designed to improve shooter performance and weapon reliability.
Performance Enhancements:
Consistent gas pressure and cycling
Reduced recoil impulse for faster follow-up shots
Stable, accurate barrel harmonics
Durable construction for long service life
A true performance upper for serious shooters and professionals.
Perfect for Tactical Shooters, Competitors & Home Defense
The 16MBUP556L upper is designed for versatility across all shooting disciplines.
Best Use Cases:
Tactical and defensive carbines
3-Gun and competition rifles
Duty and patrol rifles
Recreational and precision shooting
One upper—endless capability.
Why Choose HM Defense?
HM Defense is known for its groundbreaking firearm designs and top-tier AR-platform components trusted by professionals and enthusiasts alike.
HM Defense Advantages:
Patented MonoBloc technology
Superior materials and machining
Reliability-focused engineering
American-made craftsmanship
Choose HM Defense for innovation backed by proven performance.
Key Specifications
Brand: HM Defense
Model: 16MBUP556L
Calibers: 5.56x45mm NATO / .223 Rem
Barrel Length: 16" MonoBloc Barrel
Barrel Finish: Black Cerakote
Receiver Material: 7075-T6 Aluminum
Receiver Finish: Black Anodized
Handguard: 15" M-LOK Free-Float with Long Rail
Compatibility: AR-15 Platform
UPC: 854164007234
Final Thoughts
The HM Defense MonoBloc Upper (16MBUP556L) is a high-performance, feature-packed upgrade for any AR-15 shooter who demands the best. With its patented MonoBloc Barrel design, rugged Cerakote finish, precision 7075-T6 receiver, and modular M-LOK handguard, this upper delivers unmatched reliability, accuracy, and customization potential. Whether you're building a tactical rifle, competition setup, or home-defense platform, the HM Defense MonoBloc Upper is engineered to elevate your AR to elite levels of performance.
Choose HM Defense for innovation, strength, and next-level shooting capability.
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