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Rock River Arms 9mm Magwell Conversion Block AR15 RRA Adapter
Rock River Arms 9mm Magwell Conversion Block AR15 RRA Adapter

Rock River Arms 9mm Magwell Conversion Block AR15 RRA Adapter

Part Number:9MM0115
On sale: $174.95
Retail Price:$185.00
You Save:$10.05(5%)
In Stock.

Rock River Arms RRA 9mm Magwell Conversion Block AR15 AR-15 Adapter

The RRA Enhanced 9mm Mag Well Block for lower receivers WITHOUT integral magwell is a reliable, and most importantly affordable Mag-Well Block that no other on the market can compare to. The one-piece design offers the same advantages that are found in having a dedicated 9mm lower but without all of the dis-advantages that come with it!

Compatible magazines:
-Spike's Tactical/Metalform
-Modified Uzi
-Beta-C drums

As you can see, you have a great selection of mags to choose from so you won’t be stuck with only having to buy one manufacturer’s magazine! Installation of the block is a breeze. The entire installation process takes less than 5 minutes to get the block up and running inside of your lower and takes about 5 minutes to take it out, so it’s perfect for you guys who love to switch calibers at the range all day. There is zero gunsmithing required and zero permanent modifications to the rifle/pistol are made. The block also utilizes the standard AR-15 bolt catch so you won’t need to change it out for another aftermarket part.

Let’s talk about reliability. The absolute biggest flaw with the 9mm platform is that there isn’t the ability to have the needed adjustability to work with a wide variety of aftermarket parts, magazines, and ammo. Our block features an extra wide mag catch slot that allows the end-user to adjust the block up and down so that the feed ramp can be positioned perfectly every time thus increasing your reliability.

Another reliability increasing feature of the block is the patent pending adjustable ejector. This allows you to adjust the ejector up and down so it can be positioned with the bolt perfectly every time. Never again will the ejector be dragging on the bottom side of the bolt causing excessive and premature wear and the adjustment screw will also keep the ejector nice and tight; completely wobble free!

On the grounds of its construction, the main body of the block is machined from 6061 Aircraft grade Aluminum and all steel parts are machined from 4140 high carbon Chromoly steel for strength and are properly heat treated. Of course, all Aluminum parts are finished with a Mil-Spec Type III Hardcoat Anodized finish and all the steel parts are finished in a Mil-Spec Phosphate finish.

As you can see, a simple adjustment of the block can turn your single shot 9mm AR into a 100% reliable semi-auto!
Grab one today and get that unreliable 9mm AR working the way she should!

NOTE: *The block does feature a Last round hold open but the Magazine also needs the provision for it to function. *The block is NOT designed for use in an Olympic Arms system. A little installation help: *We recommend installing the block flush with the top of your receiver, we found that its a good starting point to work from. *All ejectors come pre-set to Factory height so adjustment may not be required. *The block requires SAE allen keys (Not included).


  • Increased 9mm AR reliability
  • Durable construction
  • Adjustable to fit your 9mm AR
  • ZERO gunsmithing required and ZERO permanent modifications made
  • Installs and Uninstalls in minutes


  • RRA 9mm block


Customer Reviews

4 Stars
Adapter Review
This is an easy to install adapter for 9mm. It works well and is well built. My only issue is the magazine catch. With the adapter installed the overall wall thickness leaves very little of the magazine catch to engage the magazine. Other than that, it works well.
Did you find this helpful?  1 of 1 Found Helpful
Reviewed by:  from Illinois. on 9/14/2021
5 Stars
I have two of these, one bought from VT tactical. It works 100% of the time with my ARs using modified UZI mags (no lock back though, but I deal with that by thinking "just like an HK operates"). Gripping mechanism to secure it in place does not mess up or scratch the lower. I use the conversion rather than dedicated 9 since I am behind enemy lines and there is a mag ban and AR embargo in the Democratik People's Republik of Massachusetts. VT supply was great to deal with and addressed on specific concern I had with the order wonderfully. Five star supplier in addition to five star part.
Did you find this helpful? 
Reviewed by:  from Massachsuetts. on 1/23/2022

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