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CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver 55BB40BAB Caliber: 5.56x45mm NATO, Barrel Length: 16.1 in, 15% Off w/ Free S&H

CMMG UPPER GROUP, RESOLUTE, Mk4, 5.56X45MM NATO, 16.1 in, No BCG or Charging Handle, Armor Black, M-LOK Free-Float, 55BB40BAB
CMMG UPPER GROUP, RESOLUTE, Mk4, 5.56X45MM NATO, 16.1 in, No BCG or Charging Handle, Armor Black, M-LOK Free-Float, 55BB40BAB
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CMMG UPPER GROUP, RESOLUTE, Mk4, 5.56X45MM NATO, 16.1 in, No BCG or Charging Handle, Armor Black, M-LOK Free-Float, 55BB40BAB

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Questions & Answers
Does this come with a BCG and charging handle? Expert Answer

The CMMG Resolute MK4 Upper Receiver will include the BCG and Charging Handle.

by Ethan, Gear Expert, May 20, 2024
View All Q&A You Have a Question? Ask!
Customer Reviews
Helpful Negative Review
Wrong Muzzle Device by Wrong Device, December 3, 2024
The Photo shows the upper as having a CMMG Zeroed muzzle brake, the actual upper I recieved has a standard A2 birdcage.
3/10 found this helpful
Read 1 Review
Caliber:
5.56x45mm NATO
Barrel Length:
16.1 in
Barrel Twist Rate:
1-7
Muzzle Device:
A2 Flash Hider
Finish:
Armor Black
Color:
Armor Black
Handguard Length:
25 in
Barrel Material:
4140 Chrome Moly Vanadium
Condition:
New
Additional Features:
M-LOK Free-Float

Code: 2CM-URC-55BB40BAB-55BB40BAB

MPN: 55BB40BAB

UPC: 810103473461

List: $609.95Save 15%
$516.99

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 Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver

Make the quick switch to a 5.56mm carbine with this RESOLUTE Mk4 Upper Group. This upper group does NOT include BCG or charging handle.image

Specifications for CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver:

Manufacturer: CMMG
Caliber: 5.56x45mm NATO
Barrel Length: 16.1 in
Barrel Twist Rate: 1-7
Muzzle Device: A2 Flash Hider
Finish: Armor Black
Color: Armor Black
Handguard Length: 25 in
Gun Type: Rifle
Gun Make: AR Platform
Gun Model: AR-15
Weight: 3.6 lb
Barrel Material: 4140 Chrome Moly Vanadium
Rifling Profile: Medium Taper
Magazine Included: No
Condition: New
Additional Features: M-LOK Free-Float
Threads per Inch: 1/2x28

Package Contents:

  • CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver

What firearm models does the manufacturer say CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver is compatible with?

The manufacturer says that CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver is compatible with AR-15

CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver Orderable Models

List of Orderable Models

  • CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver, Armor Black, M-LOK Free-Float Handguard for AR-Platform, No BCG or Charging Handle, 55BB40BAB , MPN: 55BB40BAB , UPC: 810103473461 , Code: 2CM-URC-55BB40BAB-55BB40BAB

CMMG Resolute MK4 5.56x45mm NATO 16.10in Upper Receiver Unavailable & Discontinued Models

List of Unorderable Models

  • CMMG Resolute MK4 5.56x45mm NATO 16.10in Uper Receiver, Midnight Bronze, M-LOK Free-Float Handguard for AR-Platform, No BCG or Charging Handle, 55BB40BMB , MPN: 55BB40BMB , UPC: 810103473508 , Code: 2CM-URC-55BB40BAB-55BB40BMB
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Last updated 2026-07-11 UTC.