Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Enjoy free shipping during the holidays! Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC and to all U.S. Military APO/FPO/DPO addresses.

Enjoy Our Extended FREE RETURNS

We want to ensure that making a return is as easy as possible! With our Hassle-Free, Extended Holiday Returns, eligible orders placed from November 12, 2025 on will benefit from an extended return deadline (January 13, 2026 or 30 days after receipt of your order - whichever is later). We'll even cover the cost of return shipping. Learn more about our Return Policy.

Shopping Cart
Government Export Restriction Government Export Restriction
Government Restriction Government Restriction
Questions & Answers
If used with an AR15 lower what mag would this use?

CMMG makes an AR magazine for 5.7x28mm which holds 32 rounds.

by JUN, Verified Owner, February 8, 2025
So can you use a regular AR15 lower with this upper ?

Yes. The upper comes with a buffer plate which has a 1913 rail for stock or brace mounting, if you choose.

by Yukonsooner, Verified Owner, October 30, 2025

14% OFF Firearm Parts

PBFDClick to Copy Coupon Code
Eligible models will have a savings offer and the coupon code to use below. Add the item to your cart and enter coupon code for savings on that select model! Expires in 9 hours. Cannot be combined with other promotions or offers.
Show In Stock Only
8 Models Available

Show with deals only:

Coupon Available
Finish
All
Color
All
Search

Product Info for CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver

The 5.7x28mm personal defense cartridge has found home with the purposefully designed 6.5 DISSENT upper group. This DISSENT upper group comes complete with BCG, lower receiver 1913 picatinny rail end plate, and the choice of seven Cerakote finishes to make it uniquely you. All you need is a Mk4/mil-spec AR15 lower receiver or CMMG Mk57 lower receiver.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 Compact Action and Radial Delayed Blowback technology, 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 5.7x28mm, 6.5in Upper Receiver:

Manufacturer: CMMG
Caliber: 5.7x28mm
Barrel Length: 6.5 in
Barrel Twist Rate: 1-9
Threads per Inch: 1/2x28
Muzzle Device: Zeroed Linear Compensator
Fabric/Material: Aluminum
Gun Rail: M-LOK
Gun Make: CMMG
Condition: New
Condition Quality: Excellent
Condition Details: Other
Magazine Included: No

Package Contents:

  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver

CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver Orderable Models

List of Orderable Models

  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Anodized Black, 57BA8AE-HCA , MPN: 57BA8AE-HCA , Code: 2CM-URC-DS5728-57BA8AE-HCA
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Coyote Tan, 57BA8AE-CT , MPN: 57BA8AE-CT , UPC: 810097509436 , Code: 2CM-URC-DS5728-57BA8AE-CT
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Armor Black, 57BA8AE-AB , MPN: 57BA8AE-AB , UPC: 810097509412 , Code: 2CM-URC-DS5728-57BA8AE-AB
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Charcoal Green, 57BA8AE-CG , MPN: 57BA8AE-CG , UPC: 810097509429 , Code: 2CM-URC-DS5728-57BA8AE-CG
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Tungsten, 57BA8AE-TNG , MPN: 57BA8AE-TNG , UPC: 810097509474 , Code: 2CM-URC-DS5728-57BA8AE-TNG
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Sniper Grey, 57BA8AE-SG , MPN: 57BA8AE-SG , UPC: 810097509450 , Code: 2CM-URC-DS5728-57BA8AE-SG
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Titanium, 57BA8AE-TI , MPN: 57BA8AE-TI , UPC: 810097509467 , Code: 2CM-URC-DS5728-57BA8AE-TI
  • CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver, 1-9 Twist, 1/2 X 28 TPI, Midnight Bronze, 57BA8AE-MB , MPN: 57BA8AE-MB , UPC: 810097509443 , Code: 2CM-URC-DS5728-57BA8AE-MB

CMMG DISSENT 5.7x28mm, 6.5in Upper Receiver Unavailable & Discontinued Models

List of Unorderable Models

  • DEMO, CMMG DISSENT Upper Receiver, 5.7x28mm, 6.5in, 1-9 Twist, 1/2x28 Thread, Zeroed Linear Compensator, Charcoal Green, 57BA8AE-CG , MPN: 57BA8AE-CG-DEMO , Code: 2CM-URC-DS5728-57BA8AE-CG-DEMO
  • DEMO, CMMG DISSENT Upper Receiver, 5.7x28mm, 6.5in, 1-9 Twist, 1/2x28 Thread, Zeroed Linear Compensator, Armor Black, 57BA8AE-AB , MPN: 57BA8AE-AB-DEMO , Code: 2CM-URC-DS5728-57BA8AE-AB-DEMO
  • USED CMMG DISSENT Upper Receiver, 5.7x28mm, 6.5in, 1-9 Twist, 1/2x28 Thread, Zeroed Linear Compensator, Armor Black, 57BA8AE-AB, EDEMO1, Condition Parts Only/Salvage, Wrong Product , MPN: 57BA8AE-AB-EDEMO1 , Code: 2CM-URC-DS5728-57BA8AE-AB-EDEMO-WP-F
  • USED CMMG DISSENT Upper Receiver, 5.7x28mm, 6.5in, 1-9 Twist, 1/2x28 Thread, Zeroed Linear Compensator, Armor Black, 57BA8AE-AB, EDEMO2, Used, Condition Fair, Inspect and Rebox , MPN: 57BA8AEAB-EDEMO2 , Code: 2CM-URC-DS5728-57BA8AE-AB-EDEMO-RE-D
Compare (0)