Daniel Defense MK18 RIII, 5.56mm, 10.3 Barrel, Black, Upper Receiver Group
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Daniel Defense
Overview
The Daniel Defense Mk18 RIII Upper Receiver Group is a stripped assembly designed for the AR-15 platform, featuring a 10.3-inch barrel optimized for 5.56 NATO ammunition. This upper receiver is crafted from 7075-T6 aluminum, ensuring a lightweight yet robust construction, making it suitable for various applications. Commonly found in builds utilizing a carbine gas system, this upper is ideal for those looking to create compact, maneuverable firearms.
Specifications
Daniel Defense MK18 RIII, 5.56mm, 10.3 Barrel, Black, Upper Receiver Group
Available Merchants(5)
Prices checked
Stock Alert
October 2026 on GunPartPicker
Daniel Defense MK18 RIII, 5.56mm, 10.3 Barrel, Black, Upper Receiver Group ranked #170 of the 844 upper receivers builders added on GunPartPicker in October 2026. Builders have added it to their builds on GunPartPicker. Since April 2026, it ranks #157 of the 2,049 upper receivers builders have added. Builds with this upper receiver are nearly all chambered in 5.56 NATO, nearly all on carbine-length gas, and nearly all AR-15.
It was hard to find in October 2026, in stock on only 7 of the 19 days we checked, and today none of the 5 retailers we track has it in stock right now. Listed prices start at $1,454 at Primary Arms for when it comes back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
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Builds Featuring This Part
See all builds →Builds in the community that include the Daniel Defense Mk18 RIII, 5.56mm, 10.3 Barrel, Black, Upper Receiver Group
| Build | Parts | Total |
|---|---|---|
 | 14 | $3788.01 |
 | 36 | $18589.86 |
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