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Rock River Arms 9mm Carbine A4 Complete Upper Half AR15 RRA

Rock River Arms 9mm Carbine A4 Complete Upper Half AR15 RRA

Part Number:9MM0450X
On sale: $549.95
Retail Price:$575.00
You Save:$25.05(4%)
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Rock River Arms 9mm Carbine Length A4 Complete Upper Half AR15 RRA


So you want to make your AR-15 multi-caliber with less expensive handgun 9mm Parabellum rounds?  It’s about time, everyone is doing it. It’s a very simple process, we’ll go through the steps here. It's easy, quick and very cool. Lower is not included and shown for example only. This is the complete upper.

  1. Replace your upper receiver with this model.
  2. Insert a 9mm Magwell such as the excellent Spike's Tactical quick change enhanced block.
  3. Use either a DPMS (non-notched) AR15 hammer or a RRA 9mm hammer. The DPMS model lets you switch between 223 and 9mm. A RRA 9mm hammer is preferred in high use (such as full auto).  Notched 223 hammers LIKE RRA AND OTHERS COMMONLY USE (see pic below) used with this upper could damage your rifle and will NOT run smoothly.
  4. Switch out your standard carbine buffer with a 9mm buffer like a YHM model (in stock).


  • 9MM Parabellum
  • 16" Chrome Moly 1:10 Twist rate
  • Forged A4 Upper Receiver
  • A1 Flash Hider 1/2 by 36 Thread
  • A2 Front Sight
  • Carbine Length Handguard Included
  • 9mm Bolt Included
  • Charging Handle Included  


Can I switch between my AR15 upper and this one easily?

Yes, You have the ability to switch uppers quickly and easily with this kit. Inspect your existing hammer and compare it with the picture below. If it is the "Sporterized" DPMS non-notched style then your are all set.  If not, buy the DPMS hammer-it works well on both uppers. Next, simply push the two upper retaining pins out, swap out your 5.56 and 9mm uppers, insert the magwell block and change your buffer. This normally takes less than 2 minutes. 

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