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CMMG
Overview
The CMMG MK4 .223 Remington AR Lower is a stripped lower receiver designed for the AR-15 platform, crafted from durable 7075-T6 aluminum and finished with a Cerakote in black. This lower is compatible with a multi-caliber setup, allowing builders to customize their firearms for various applications. It is a forged design, which adds strength and reliability, making it a solid choice for builds that typically feature a mid-length gas system and utilize the .223 Wylde caliber.
Specifications
Available Merchants(6)
Prices checked
Price Alert
November 2026 so far on GunPartPicker
CMMG MK4 .223 Remington AR Lower, Black - 55CA102AB ranks #34 of the 549 lower receivers builders have added on GunPartPicker so far in November 2026, behind the Wilson Combat Lightweight AR-10 Receiver Set Armor-Tuff, with about 1 in every 200 lower receivers added to builds. Up from #39 in October. Builds with this lower receiver are mostly chambered in 5.56 NATO (72%, then .223 Wylde 13%), split between mid-length (55%) and carbine-length (30%) gas systems, and nearly all AR-15.
It was in stock most times we checked in October 2026, and today 3 of the 6 retailers we track have it in stock. Prices barely moved in October 2026, holding around $100.02, with no real sale all month. Buying today, the lowest price is $100.02 at Classic Firearms, which matches the best price we saw in October.
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 hundreds of builds that include this one
CMMG AR-15 Mil-Spec Trigger KIT
Bravo Company Mfg Upper Receiver Assembly w/ Laser T-Markings, Hard Coated Anodized - 4-UR-M4
B5 Systems Type 22 P-Grip - Black
Timber Creek Outdoors Ambidextrous Safety Selector - Black
CMMG AR15 Ambi Mag Catch, Black - 55AFF6E
CMMG AR-15 HD Pivot and Takedown Pin Parts KIT - 55AFF3B
Build Configuration Breakdown
Aggregated and anonymized data showing how builders use this product
CaliberBased on real build data showing which calibers builders choose alongside this product.
Gas SystemBased on real build data showing which gas system lengths builders use with this product.
Builds Featuring This Part
See all builds →Builds in the community that include the CMMG MK4 .223 Remington AR Lower, Black - 55CA102AB
| Build | Parts | Total |
|---|---|---|
 | 20 | $821.79 |
 | 26 | $2856.93 |
 | 11 | $1142.66 |
 | 11 | $1438.32 |
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