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Radical Firearms
Overview
The Radical Firearms 5.56 Barreled AR-15 Upper features a complete assembly with a 16-inch barrel, designed specifically for the 5.56 NATO caliber. Its mid-length gas system provides a balanced cycling operation, which can enhance reliability and reduce recoil in your builds. This upper receiver is commonly used in builds that prioritize the mid-length gas system configuration, making it a solid choice for versatile shooting applications.
Radical Firearms 5.56 Barreled AR-15 Upper - 16" - Primary Arms Exclusive
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Builders have been adding the Radical Firearms 5.56 Barreled AR-15 Upper - 16" - Primary Arms Exclusive to their builds on GunPartPicker since January 2026. All time, it ranks #423 of the 1,569 upper receivers builders have added. Builds with this upper receiver are nearly all chambered in 5.56 NATO, nearly all on mid-length gas, and nearly all AR-15.
Updated · from real builds on GunPartPicker
We ranked every upper receiver by how often it shows up in real builds on GunPartPicker.
Read the guide: Most Popular AR-15 Upper Receivers →The part most often added in each category by the 209 builds that include this one
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Builds in the community that include the Radical Firearms 5.56 Barreled Ar-15 Upper - 16" - Primary Arms Exclusive
| Build | Parts | Total |
|---|---|---|
 | 8 | $519.48 |
 | 26 | $1196.29 |
 | 19 | $3309.75 |
 | 12 | $730.07 |
 | 21 | $1142.27 |
 | 14 | $1229.73 |
| 12 | $1521.10 |
| 8 | $1157.90 |
 | 15 | $1244.71 |
 | 8 | $477.93 |
| 10 | $559.87 |
 | 32 | $2884.49 |
2 global ratings
Top reviews
radical firearms 16 inch barreled upper, primary arms BCG included. lines up perfect with my mil spec lower, takedown pins slip without rocking. ran 200 rds with no malfs. great value for a complete upper assembly
Radical Firearms upper is a budget option for a complete build. Cerakote finish is on the thicker side which made my BCG run tight for the first 100 rounds before it broke in. Once worn in cycles fine. Decent for a parts build, wouldnt run a high pressure load on it.