CMMGAll CMMG upper receivers

Resolute(R) MK4 5.56 NATO Assembled Upper Receiver W/P&W Brake - Resolute MK4 5.56NATO Assembl Upper 14.5''''BBL W/P&W Brake Black

CMMG Resolute(R) Mk4 5.56 Nato Assembled Upper Receiver W/P&W Brake - Resolute Mk4 5.56nato Assembl Upper 14.5''''bbl W/P&W Brake Blk - Upper Receiver for AR-15 - view 1
CMMG Resolute(R) Mk4 5.56 Nato Assembled Upper Receiver W/P&W Brake - Resolute Mk4 5.56nato Assembl Upper 14.5''''bbl W/P&W Brake Blk - Upper Receiver for AR-15 - view 2
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Overview

The CMMG Resolute Mk4 5.56 NATO Assembled Upper Receiver is a complete upper assembly featuring a 14.5-inch barrel designed specifically for the AR-15 platform. This upper is chambered in 5.56 NATO, offering versatility and compatibility with a wide range of ammunition. Builders often integrate this upper into compact, lightweight configurations ideal for tactical applications and home defense setups.

Specifications

MPN55B360B-AB
Barrel Length14.5
AssemblyComplete
PlatformAR-15
ColorBlack
Caliber5.56 NATO

Available Merchants(2)

Prices checked

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BattleHawk Armory logo
BattleHawk Armory
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Out of Stock
$433
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Brownells
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$525
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Build history on GunPartPicker

Builders on GunPartPicker first added the CMMG Resolute(R) MK4 5.56 NATO Assembled Upper Receiver W/P&W Brake - Resolute MK4 5.56NATO Assembl Upper 14.5''''BBL W/P&W Brake Black to a build in February 2026.

It was out of stock everywhere we track for all of September 2026, and today none of the 2 retailers we track has it in stock right now. Listed prices start at $432.70 at BattleHawk Armory for when it comes back.

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Frequently Built With

The part most often added in each category by the builds that include this one

Smith & Wesson M&P15 Complete Lower 5.56x45mm/.223 Remington, Black - 812002

Smith & Wesson M&P15 Complete Lower 5.56x45mm/.223 Remington, Black - 812002

Lower Receiver$339in 25% of them
Breek Arms AR-15 Warhammer MOD2 Ambidextrous Charging Handle Black

Breek Arms AR-15 Warhammer MOD2 Ambidextrous Charging Handle Black

Charging Handle$50in 25% of them
WMD Guns 5.56 AR-15 Bolt Carrier Group With Hammer - NIB-X Finish

WMD Guns 5.56 AR-15 Bolt Carrier Group With Hammer - NIB-X Finish

Bolt Carrier Groupin 25% of them
Rise Armament AR-15 Le/military Single-Stage Trigger 4.5lb

Rise Armament AR-15 Le/military Single-Stage Trigger 4.5lb

Trigger$99in 13% of them
XTS M-LOK Aluminum Angled Foregrip - Black

XTS M-LOK Aluminum Angled Foregrip - Black

Foregrip$14in 13% of them
Streamlight ProTac Rail Mount HL-X Laser 1000 Lumen Weapon Light with Tape Switch - CR123A

Streamlight ProTac Rail Mount HL-X Laser 1000 Lumen Weapon Light with Tape Switch - CR123A

Light$156in 13% of them

Build Configuration Breakdown

Aggregated and anonymized data showing how builders use this product

Gas System

50.4%
Mid-Length50.4%
Carbine25.9%
Pistol11.2%
Rifle11%
Blowback1.3%
Other0.3%

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