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CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver Up to 15% Off w/ Free Shipping — 4 models

CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Armor Black, 30B0E67-AB
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Midnight Bronze, 30B0E67-MB
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Tungsten, 30B0E67-TNG
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Coyote Tan, 30B0E67-CT
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Armor Black, 30B0E67-AB
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CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Armor Black, 30B0E67-AB
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Midnight Bronze, 30B0E67-MB
2 of 4 images
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Midnight Bronze, 30B0E67-MB
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Tungsten, 30B0E67-TNG
3 of 4 images
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Tungsten, 30B0E67-TNG
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Coyote Tan, 30B0E67-CT
4 of 4 images
CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Coyote Tan, 30B0E67-CT

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Questions & Answers
does this have ejection port cover? Expert Answer

Yes, the CMMG Dissent Mk4, 300BLK, 6.5in Upper Receiver features an AR15 style ejection port cover.

by Ethan, Gear Expert, February 17, 2025
Is it full auto capable Can you answer this question?
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Customer Reviews
Helpful Positive Review
Well made pdw upper from cmmg by Jimothy, Verified Owner, June 14, 2024
If you want a buffer-less pdw length upper under 9 inches compatible with a Milspec ar lower there aren’t a lot of options out there. The only other option with a 6 inch barrel I can think of is the sig rattler upper but those cost about $600 more th...
Read More...
4/4 found this helpful
Helpful Positive Review
6.5" Dissent 300BLK by The Bull, Verified Owner, July 19, 2024
This thing is perfect for 300blkout home defense and it is reliable.Cmmg is a awesome company that makes great products and has top notch customer service as does opticsplanet with fast shipping and the best prices.
2/2 found this helpful
Most Recent Reviews
Mk4 300 Blackout Upper by Marc, Verified Owner, May 10, 2025
Love it. Great quality and perfect fit on Dissent lower. No malfunctions in first 60 rounds. Good accuracy with Holoson red dot at 50 yards. Fun to shoot.
Read All 3 Reviews
4 Models Available
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ATTENTION! We currently do not ship this product to P.O. Boxes, AK, CA, CT, DE, HI, MA, NJ, NY, U.S. Territories, or select Colorado locations. Please see our policies for more information or a detailed list of locations.

Product Info for CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver

Pack some 30 Cal power into a pint size PDW. Perfect for your existing Mk4 DISSENT lower or standard AR15 lower group, this upper group combines utility, innovation, and unmatched style that lets you build or swap your DISSENT to 300BLK. Take your pick from seven unique Cerakote finishes, curated for even the most discerning tastes.image

Its no secret that pistol stabilizing braces have been a target for scrutiny over the years, and those that enjoy building their own AR pistols have wondered what will come out of all the uncertainty. DISSENT is our answer. Utilizing our patent pending direct impingement Compact Action, DISSENT upper groups house the entire action and recoil assembly in the upper receiver resulting in less bulk and length than traditional AR pistols. The forward non-reciprocating side charger allows for quick bolt operation without coming off target.

DISSENT Upper groups include a 1913 Picatinny rail end plate to use in place of the lower receiver buffer tube.

Specifications for CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver:

Manufacturer: CMMG
Caliber: .300 AAC Blackout
Barrel Length: 6.5 in
Barrel Twist Rate: 1-7
Firearms Threads Per Inch: 5/8x24
Muzzle Device: Zeroed Linear Compensator
Finish: Cerakote
Fabric/Material: Aluminum
Gun Rail: M-LOK
Gun Make: CMMG
Gun Model: CMMG Mk4
Magazine Included: No
Condition Details: Other
Condition: New
Condition Quality: Excellent

Package Contents:

  • CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver

What firearm models does the manufacturer say CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver is compatible with?

The manufacturer says that CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver is compatible with CMMG Mk4

CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver Orderable Models

List of Orderable Models

  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Midnight Bronze, 30B0E67-MB , MPN: 30B0E67-MB , UPC: 810097509238 , Code: 2CM-URC-DS3065-30B0E67-MB
  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Armor Black, 30B0E67-AB , MPN: 30B0E67-AB , UPC: 810097509207 , Code: 2CM-URC-DS3065-30B0E67-AB
  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Tungsten, 30B0E67-TNG , MPN: 30B0E67-TNG , UPC: 810097509269 , Code: 2CM-URC-DS3065-30B0E67-TNG
  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Coyote Tan, 30B0E67-CT , MPN: 30B0E67-CT , UPC: 810097509221 , Code: 2CM-URC-DS3065-30B0E67-CT

CMMG DISSENT Mk4, 300BLK, 6.5in Upper Receiver Unavailable & Discontinued Models

List of Unorderable Models

  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Anodized Black, 30B0E67-HCA , MPN: 30B0E67-HCA , Code: 2CM-URC-DS3065-30B0E67-HCA
  • DEMO, CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Titanium, 30B0E67-TI , MPN: 30B0E67-TI-DEMO , Code: 2CM-URC-DS3065-30B0E67-TI-DEMO
  • USED, CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Tungsten, 30B0E67-TNG , MPN: 30B0E67-TNG-EDEMO , Code: 2CM-URC-DS3065-30B0E67-TNG-EDEMO-MI-U
  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Charcoal Green, 30B0E67-CG , MPN: 30B0E67-CG , UPC: 810097509214 , Code: 2CM-URC-DS3065-30B0E67-CG
  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Titanium, 30B0E67-TI , MPN: 30B0E67-TI , UPC: 810097509252 , Code: 2CM-URC-DS3065-30B0E67-TI
  • CMMG DISSENT Upper Receiver, Mk4, 300BLK, 6.5in, 1-7 Twist, 5/8x24 Thread, Zeroed Linear Compensator, Sniper Grey, 30B0E67-SG , MPN: 30B0E67-SG , UPC: 810097509245 , Code: 2CM-URC-DS3065-30B0E67-SG
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Last updated 2026-07-24 UTC.