CMMG DISSENT Mk4 Upper — 300 Blackout, 6.50" Barrel — Left-Side Charging — Armor Black — ZEROED™ Linear Comp — 4.60" M-LOK® Handguard — Picatinny End Plate — AR-15 Platform — Model 30B0E67AB — UPC 810097509207

Build a compact, hard-hitting PCC/SBR with the CMMG DISSENT Mk4 6.50" 300 Blackout Upper in Armor Black. Purpose-engineered for maneuverability and modern ergonomics, this upper pairs a 6.50" 300 BLK barrel with a left-side charging handle, a blast-taming ZEROED™ Linear Comp, and a minimalist 4.60" free-float M-LOK® handguard. A Picatinny end plate extends accessory options, while the DISSENT architecture streamlines manipulations for fast, confident control on the range or in close quarters.

Note: Listing describes the upper receiver assembly. See Included / Not Included below to confirm components for your specific package.

Why Choose the DISSENT Mk4 6.5" 300 BLK Upper

• 300 Blackout versatility in a micro package: Run supersonic loads for defense or hunting and subsonic loads for suppressed use (where legal) — all from the 6.50" barrel optimized for compact builds.

• Left-side charging efficiency: Keep your firing hand anchored while you charge, clear, or perform press checks with the support hand — ideal behind cover or in tight interiors.

• ZEROED™ Linear Comp: Directs blast and concussion downrange, improving shooter comfort compared to side-venting brakes — a smart choice for short-barrel .300 BLK.

• 4.60" free-float M-LOK® handguard: Rigid, lightweight rail with M-LOK slots for lights, hand stops, and QD sling points without front-end bulk.

• Armor Black finish: Low-glare, durable coating stands up to hard training cycles and real-world weather.

• Picatinny end plate: Adds rear rail real estate for sling hardware and accessories, keeping the setup modular and mission-ready.

Key Specs (At a Glance)

• Platform: AR-15 / CMMG DISSENT Mk4 upper receiver group

• Caliber: .300 AAC Blackout (300 BLK)

• Barrel Length: 6.50 inches

• Muzzle Device: CMMG ZEROED™ Linear Comp (installed)

• Handguard: 4.60" free-float M-LOK® aluminum

• Charging: Left-side charging handle

• Rear Interface: Picatinny end plate

• Finish/Color: Armor Black

• Model / SKU: 30B0E67AB

• UPC: 810097509207

Designed for Real-World Performance

Short-barrel 300 BLK shines in CQB and vehicle roles, and this DISSENT upper is built to exploit that strength. The linear comp pushes pressure forward for a more pleasant shooting experience, especially indoors or around teammates. The free-float handguard maintains accuracy while offering just enough rail length for critical accessories and ergonomic indexing without unnecessary weight.

Build Notes & Compatibility

• Lower receivers: Pairs with most mil-spec AR-15 lowers. Confirm your brace/stock and buffer system to comply with local laws and your intended configuration.

• BCG & charging handle: DISSENT uppers often use platform-specific charging solutions; follow CMMG guidance for bolt carrier group and charging compatibility.

• Magazines: Use quality AR-15 magazines designed for 300 BLK for best feeding across bullet profiles.

• Optics & sights: Flat-top upper accepts red dots, prisms, or LPVOs; the short handguard supports offset lights/sights as desired.

• Suppressed use: For subsonic loads with a suppressor (where legal), consider tuning (adjustable gas / buffer) for optimal reliability.

Ideal Use Cases

• Home & personal defense: Compact OAL, soft-shooting subsonic options, and efficient blast management.

• Vehicle & low-profile roles: Short package with forward-directed concussion for confined environments.

• Training & classes: Side-charging ergonomics and M-LOK® real estate for modern sling/light setups.

• Hunting (where appropriate): Supersonic .300 BLK loads deliver solid terminal performance at close-to-mid ranges.

What’s Included / Not Included

Included (typical):

• CMMG DISSENT Mk4 Upper, 6.50" 300 BLK barrel

• ZEROED™ Linear Comp (installed)

• 4.60" Free-float M-LOK® handguard

• Left-side charging assembly (as configured by CMMG)

• Picatinny end plate

Not Included (verify package):

• Bolt Carrier Group (BCG)

• Sights/optics, sling, lower receiver assembly, magazines

Always check the exact contents of your shipment; configurations may vary by retailer or batch.

Setup & Zeroing Tips

1. Verify safe/clear on your lower; separate upper/lower per AR procedures.

2. Pin the upper to your AR-15 lower and install the recommended BCG/charging solution.

3. Torque & threadlocker: Follow manufacturer specs for mounts and accessories.

4. Function test with your intended ammo (supersonic/subsonic).

5. Zero at your preferred distance (25–50 yards common for PDW builds); record dope for both load types.

Care & Maintenance

• Keep the chamber, bore, and gas path clean; lube per BCG manufacturer recommendations.

• Re-check handguard and muzzle device torque after first 100–200 rounds.

• Suppressed shooting increases fouling — shorten cleaning intervals accordingly.

Safety & Compliance

• Use only quality .300 AAC Blackout ammunition from reputable manufacturers.

• Follow all federal, state, and local laws regarding barrel length, stocks/braces, suppressors, and transport.

• Confirm headspace and component compatibility when installing your BCG.

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CMMG DISSENT Mk4 upper, 6.5" 300 Blackout side-charging upper, Armor Black AR-15 upper, ZEROED Linear Comp, 4.60" M-LOK handguard, Picatinny end plate, compact 300 BLK AR upper, 30B0E67AB, UPC 810097509207.

Compact. Controllable. Configurable. The CMMG DISSENT Mk4 6.50" 300 Blackout Upper combines left-side charging, a ZEROED™ Linear Comp, and a free-float M-LOK® handguard to deliver a modern, maneuverable AR build with .300 BLK flexibility.

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