Rock River Arms Completed Pistol Upper Receiver A4 .223/5.56mm 10.5 Inch Barrel 1-7 Twist 1/2-28 Thread Free-Float Handguard A2 Flash Hide Black
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Rock River Arms
Overview
The Rock River Arms Completed Pistol Upper Receiver A4 is a fully assembled unit designed for the AR-15 platform, featuring a 10.5-inch barrel optimized for 5.56 NATO ammunition. With a 1:7 twist rate, it effectively stabilizes a range of bullet weights, making it versatile for various shooting applications. This upper is commonly found in short-barreled builds, often favored by those seeking compact and maneuverable configurations for close-quarters use.
Specifications
Rock River Arms Completed Pistol Upper Receiver A4 .223/5.56mm 10.5 Inch Barrel 1-7 Twist 1/2-28 Thread Free-Float Handguard A2 Flash Hide Black
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Stock Alert
September 2026 on GunPartPicker
Rock River Arms Completed Pistol Upper Receiver A4 .223/5.56mm 10.5 Inch Barrel 1-7 Twist 1/2-28 Thread Free-Float Handguard A2 Flash Hide Black ranked #267 of the 615 upper receivers builders added on GunPartPicker in September 2026. Builders on GunPartPicker first added it to a build in July 2026.
Today the one retailer we track is out of stock. Listed prices start at $549.99 at Optics Planet for when it comes back.
Updated · from real builds on GunPartPicker · Prices checked · refreshed daily across 37 retailers
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