Resolute(R) MK4 300 Blackout Assembled Upper Receiver W/P&W Brake - Resolute MK4 300BLK Assembl Upper 14.5''''BBL W/P&W Brake Black
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Overview
The CMMG Resolute Mk4 300 Blackout Assembled Upper Receiver is a complete upper designed specifically for the AR-15 platform, featuring a 14.5-inch barrel optimized for 300 Blackout ammunition. This configuration allows for enhanced performance in both suppressed and unsuppressed shooting, making it a versatile choice for various applications. Builders typically integrate this upper in 300 Blackout builds, capitalizing on its compact size and effective caliber for tactical or hunting purposes.
Specifications
Resolute(R) MK4 300 Blackout Assembled Upper Receiver W/P&W Brake - Resolute MK4 300BLK Assembl Upper 14.5''''BBL W/P&W Brake Black
Build history on GunPartPicker
Builders have been adding the CMMG Resolute(R) MK4 300 Blackout Assembled Upper Receiver W/P&W Brake - Resolute MK4 300BLK Assembl Upper 14.5''''BBL W/P&W Brake Black to their builds on GunPartPicker since February 2026. All time, it ranks #643 of the 1,683 upper receivers builders have added.
Availability is good: it was in stock at one retailer or another nearly every day in September 2026, and today 2 of the 3 retailers we track have it in stock. It dipped to $432.70 at BattleHawk Armory for a stretch in September 2026, well under its usual $595.38, so sales do come around. Buying today, the lowest price is $519.99 at Optics Planet, above September's low of $432.70, so a better deal may come back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
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Frequently Built With
The part most often added in each category by the builds that include this one
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Magpul M-LOK AFG Angled Foregrip - Black
Breek Arms AR-15 Warhammer MOD2 Ambidextrous Charging Handle Black
VISM SPD FlipDot Red-Dot Reflex Sight - 2 MOA Dot Precision Red-Dot Sight with Flip-Up Lens for Fast Aiming - VDBSOLFLIP
SilencerCo Omega 300 Suppressor | 30 Caliber
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