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Rock River Arms A4 .223/5.56mm Completed Pistol Upper Up to $50.01 Off w/ Free S&H — 7 models

Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 7 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, A2 Flash Hide, Black, AR0365B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 20 Inch Barrel, Standart Profile, 1-9 Twist, 1/2-28 Thread, A2 Handguard, A2 Flash Hider w/Gas Block, Black, AR0450B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider w/Gas Block, Black, AR0388B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider, Black, AR0375B
Rock River Arms Completed Upper Receiver, A4 .223/5.56mm, 10.5 Inch Barrel, 1-7 Twist, 1/2-28 Thread, R4 Handguard, A2 Flash Hide, Black, AR0364B
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, AR0366B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 4.5 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, Vortex Flash Hider, Black, AR0369B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 7 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, A2 Flash Hide, Black, AR0365B
1 of 7 images
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 7 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, A2 Flash Hide, Black, AR0365B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 20 Inch Barrel, Standart Profile, 1-9 Twist, 1/2-28 Thread, A2 Handguard, A2 Flash Hider w/Gas Block, Black, AR0450B
2 of 7 images
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 20 Inch Barrel, Standart Profile, 1-9 Twist, 1/2-28 Thread, A2 Handguard, A2 Flash Hider w/Gas Block, Black, AR0450B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider w/Gas Block, Black, AR0388B
3 of 7 images
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider w/Gas Block, Black, AR0388B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider, Black, AR0375B
4 of 7 images
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider, Black, AR0375B
Rock River Arms Completed Upper Receiver, A4 .223/5.56mm, 10.5 Inch Barrel, 1-7 Twist, 1/2-28 Thread, R4 Handguard, A2 Flash Hide, Black, AR0364B
5 of 7 images
Rock River Arms Completed Upper Receiver, A4 .223/5.56mm, 10.5 Inch Barrel, 1-7 Twist, 1/2-28 Thread, R4 Handguard, A2 Flash Hide, Black, AR0364B
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, AR0366B
6 of 7 images
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, AR0366B
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 4.5 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, Vortex Flash Hider, Black, AR0369B
7 of 7 images
Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 4.5 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, Vortex Flash Hider, Black, AR0369B

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Most Recent Reviews
upper receiver by Skinnier, Verified Owner, February 24, 2026
Awesome product. Well built and sturdy. Very pleased
Read 1 Review
7 Models Available
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ATTENTION! We currently do not ship this product to P.O. Boxes, AK, CA, CT, DE, HI, MA, NJ, NY, U.S. Territories, or select Colorado locations. Please see our policies for more information or a detailed list of locations.

Product Info for Rock River Arms A4 .223/5.56mm Completed Pistol Upper

Manufactured to be a great product for nearly anyone, we're confident you'll love the Rock River Arms A4 .223/5.56mm Completed Pistol Upper.image

These AR15 Upper Receivers through the skilled product professionals at Rock River Arms are designed by using heavy duty and dependable materials, in order to provide you with product that will be beneficial for a long time. Manufactured utilizing some of the very best attainable materials and construction, these AR15 Upper Receivers from the product specialists at Rock River Arms can last you an incredibly long time.

Rock River Arms has been developing top quality products for a number of years, and the Rock River Arms A4 .223/5.56mm Completed Pistol Upper is their particular means of revealing just how much they are concerned.

Right here at OpticsPlanet, we ensure that it is our responsibility to receive the most suitable product for all of your requirements, and presenting the Rock River Arms A4 .223/5.56mm Completed Pistol Upper is a thing that we are happy to offer.

WARNING: California`s Proposition 65

Specifications for Rock River Arms A4 .223/5.56mm Completed Pistol Upper:

Manufacturer: Rock River Arms
Caliber: 5.56x45mm NATO, .223 Wylde
Firearms Threads Per Inch: 1/2x28
Handguard Type: Free-Float
Finish: Anodized
Color: Black
Fabric/Material: A2 Thermo Mold
Gas Block Journal Size-Diameter: .750 in
Handguard Style: Quad Rail
Gun Rail: Full Top Rail
Barrel Material: Chrome Moly
Bolt Carrier Group Included: COM-SPEC
Charging Handle Included: COM-SPEC
Magazine Included: No
Included Accessories: None
Mount Type: M-LOK

Package Contents:

  • Rock River Arms A4 .223/5.56mm Completed Pistol Upper
  • Bolt Carrier Group
  • Charging Handle Assembly

Rock River Arms A4 .223/5.56mm Completed Pistol Upper Orderable Models

List of Orderable Models

  • 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, AR0366B , MPN: AR0366B , UPC: 842834125524 , Code: 1WN-UFH-A4223-AR0366B
  • Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 20 Inch Barrel, Standart Profile, 1-9 Twist, 1/2-28 Thread, A2 Handguard, A2 Flash Hider w/Gas Block, Black, AR0450B , MPN: AR0450B , UPC: 842834107759 , Code: 1WN-UFH-A4223-AR0450B
  • Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 7 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, A2 Flash Hide, Black, AR0365B , MPN: AR0365B , UPC: 842834100088 , Code: 1WN-UFH-A4223-AR0365B
  • Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider w/Gas Block, Black, AR0388B , MPN: AR0388B , UPC: 842834107698 , Code: 1WN-UFH-A4223-AR0388B
  • Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 16 Inch Barrel, Mid-Length Profile, 1-9 Twist, 1/2-28 Thread, A2 Flash Hider, Black, AR0375B , MPN: AR0375B , UPC: 842834107681 , Code: 1WN-UFH-A4223-AR0375B
  • Rock River Arms Completed Upper Receiver, A4 .223/5.56mm, 10.5 Inch Barrel, 1-7 Twist, 1/2-28 Thread, R4 Handguard, A2 Flash Hide, Black, AR0364B , MPN: AR0364B , UPC: 842834107674 , Code: 1WN-UFH-A4223-AR0364B
  • Rock River Arms Completed Pistol Upper Receiver, A4 .223/5.56mm, 4.5 Inch Barrel, 1-9 Twist, 1/2-28 Thread, Free-Float Handguard, Vortex Flash Hider, Black, AR0369B , MPN: AR0369B , UPC: 842834124725 , Code: 1WN-UFH-A4223-AR0369B
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