CMMG Receiver Extension Nut, MK4 - 55CA9CB
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CMMG
Overview
The CMMG Receiver Extension Nut, Mk4 is a stripped component designed to secure the buffer tube to the receiver of your AR-15. Made from steel and finished with phosphate, this nut provides durability and resistance to wear, ensuring a reliable fit during assembly. You'll commonly find this part in a variety of builds where a sturdy and dependable buffer tube attachment is essential.
Specifications
Available Merchants(8)
Prices checked
Price Alert
Build history on GunPartPicker
Builders have been adding the CMMG Receiver Extension Nut, MK4 - 55CA9CB to their builds on GunPartPicker since April 2026. All time, it ranks #61 of the 163 buffer tube kits builders have added.
It was in stock most days in September 2026, and today 5 of the 8 retailers we track have it in stock. Prices barely moved in September 2026, holding around $8.46, so there haven't been real sales lately. Buying today, the lowest price is $8.79 at Palmetto State Armory.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
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