CMMG RESOLUTE Mk4 Upper — 300 Blackout, 16.10" Barrel — Armor Black — Free-Float M-LOK Handguard — AR-15 Platform (No BCG or Charging Handle) — Model 30BC40AAB — UPC 810103473393
Unlock the full potential of .300 Blackout on your AR-15 with the CMMG RESOLUTE Mk4 16.10" Upper in Armor Black. Designed for reliability and accuracy, this upper pairs a 16.10-inch .300 BLK barrel with a lightweight, free-float M-LOK® handguard—giving you a stable, modular platform for optics, lights, lasers, and mission-specific accessories. Purpose-built for the AR-15 pattern and delivered without a BCG or charging handle, it’s perfect for builders who want to drop in their preferred components and tune the gun to their ammo and use case.
Why Choose the CMMG RESOLUTE Mk4 in 300 BLK
.300 Blackout versatility: Run supersonic loads for hunting/defense performance or subsonic (where legal) for suppressed shooting and low-signature training—same magazines, same lower.
16.10" barrel balance: Optimizes sight radius and velocity in a compact, handy upper that’s easy to shoulder and maneuver.
Free-float M-LOK handguard: Rigid, lightweight rail enhances accuracy potential and offers ample M-LOK slots for modern accessories without excess bulk.
Armor Black finish: Durable, low-glare coating that resists wear and blends with most duty and range builds.
Builder-ready: Ships without BCG/CH so you can install your favorite bolt carrier group and charging handle—ideal for experienced AR owners and custom builds.
Key Specs (Quick Look)
Platform: AR-15 / CMMG RESOLUTE Mk4 upper receiver group
Caliber: .300 AAC Blackout (300 BLK)
Barrel Length: 16.10 inches
Handguard: Free-float M-LOK® aluminum handguard
Receiver Finish/Color: Armor Black
Bolt Carrier Group (BCG): Not included
Charging Handle: Not included
Model / SKU: 30BC40AAB
UPC: 810103473393
Compatibility Tip: Pairs with standard AR-15 lowers and accepts typical STANAG/AR-15 magazines. For best reliability with a broad range of .300 BLK loads, many shooters prefer magazines marketed specifically for .300 Blackout.
Designed for Real-World Performance
The RESOLUTE Mk4 is a proven foundation for home defense, range training, and hunting. The free-float M-LOK handguard keeps pressure off the barrel for consistent accuracy while giving you the freedom to mount a white light, sling QD, hand stop, or bipod right where you need them. Pair it with a red dot, LPVO, or thermal optic—.300 BLK’s flexible ballistic profile excels from short to mid-range applications.
Build-Friendly Features
Modular rail real estate: Multiple M-LOK slots at 3, 6, and 9 o’clock support clean cable routing and ergonomic setups.
Low maintenance: Armor Black exterior is easy to wipe down and stands up to hard use.
Tune it your way: Choose your own BCG (coating, gas key staking, weight) and charging handle (ambi, gas-busting, extended latch) to suit suppressed or unsuppressed shooting.
Ideal Use Cases
Suppressed shooting (where legal): Subsonic .300 BLK pairs naturally with suppressors for reduced signature.
Hunting: Supersonic loads deliver excellent terminal performance on appropriate game within caliber-appropriate distances.
Training & defense: Manageable recoil and effective energy from short to mid-range with quality ammunition.
What’s Included / Not Included
Included:
Not Included (required to complete the upper):
Installation & Setup Notes
Verify clear and safe. Separate your lower receiver per AR-15 procedures.
Attach the upper. Pin the RESOLUTE Mk4 upper to your AR-15 lower.
Add your BCG/CH. Install your preferred .223/5.56/.300 BLK AR-15 BCG and charging handle.
Function check. Confirm proper cycling and safety operation before live fire.
Zero your optic. Validate with your chosen supersonic and/or subsonic loads; record dope for both.
Care & Maintenance
Keep the chamber, extension, and gas path clean; lube lightly at friction points.
Inspect the handguard screws and rail hardware periodically; torque per manufacturer guidance.
If running suppressed, consider more frequent cleaning and lube intervals due to increased fouling.
Safety & Compliance
Use only factory-spec .300 AAC Blackout ammunition appropriate for your firearm.
Always follow federal, state, and local laws regarding ownership, configuration, and suppressed use.
Ensure proper headspace and component compatibility when installing your BCG.
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Modular. Accurate. Ready to customize. The CMMG RESOLUTE Mk4 16.10" .300 Blackout Upper in Armor Black gives you a rugged, M-LOK-equipped foundation to build your ideal AR—just add your favorite BCG, charging handle, and optic.
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