Prowin AR9 MWS Adapter – An Honest Review

So you want to build a 9mm MWS?

So you want to know about the Prowin 9mm Adapter for the MWS? Well, may I be the first to congratulate you into entering the small but passionate group of 9mm pistol calibre carbine lovers! We’re a particular bunch, but we’re enthusiastic about achieving our end goal, a MWS based AR that takes TM spec Glock mags. 

First, let’s talk about what you get in the kit. Well, you get the adapter of course, with its 95% aluminium build with the occasional steel spring and screw. The adapter itself looks great and the machining is what we expect to see from Prowin. The kit also comes with two special nozzles that have been created specifically for use with Glock mags. The nozzle is where most of the magic happens, as the actual router face has been moved down so that it properly engages with the Glock magazine when placed in the mag well. The kit also comes with three, 44rd closed front G Spec magazines which are probably one of the highlights of the kit. They are incredibly gas efficient and make for a great upgrade in any Glock spec gas pistol that takes TM spec mags. When used in a pistol, however, some oddities occur since the exit valve is slightly longer too, which causes a slight immature light strike when used in a G spec pistol. This isn’t an issue if you cock the slide, however. I believe the longer valve is to improve overall gas release which is apparent since the mags propel most pistols I’ve tested much harder than stock TM G Mags. I’ve also tested this on a worn, 5-year-old WE G18 and the full-auto fire using the Prowin mag is insane! Great rate of fire, recoil as well as a minimal cooldown. 10/10 for the three mags that come with the kit. 

So.. how is the adapter? I hear you ask. Well, first of all, it’s expensive. Delivered to my door in the UK, after postage and customs, it ended up being a £270 kit. This brings me to my first point which is the price. This is going to be a huge negative for most people since we all hate parting with our hard-earned cash. For most MWS users in this group, £270 is an insane amount of money to buy a mag adapter, two nozzles and three mags. It’s almost the price of the gun itself! (If you bought the original first-gen MWS’s in Hong Kong as I luckily did.)

Despite the price, however, the kit itself works pretty well. Good gas efficiency from the mags that come with it, and since it’s compatible with most Glock mags on the market (TM, Old Vfc & WE), you get pretty good efficiency out of those too. I would HIGHLY suggest using a lighter aluminium bolt however since the original videos that Prowin released must have been shot using the stock heavy MWS bolt. The system livens up so much with a lighter aluminium bolt and makes the cyclical rate, the snappiness and also recoil much more fun. 

Most people will wonder why someone would pay that much just to be able to get a Glock mag in an MWS. Functionally, it does the same thing, doesn’t it? Well. I bring you on to the next benefit. Aesthetics. The look of the adapter kit in most MWS receivers is pretty nice since the footprint is small and you still get a nice angle from the magazine (which looks better than the straight mags in my opinion.) 

Looks are ultimately why I chose to buy this kit since it was an early pipeline dream to have a 9mm MWS. Now that this dream has manifested, it almost seems surreal since I never thought the kit would come out! If you talk about rarity, this kit hits the spot. To my knowledge, this is currently the only 9mm AR GBB system on the market. 


Now. We get onto some of the negatives of this system/adapter in terms of the performance as well as the modifications needed to get the system running. 

Sadly, the base MWS system does need a fair amount of modifications to get the gun up and running fully. The kit itself does come with a brief guide, however, I found the photos on Prowin’s website to be far more informational. The first (fairly huge) drawback of the kit is that the bolt lock function won’t work until you do fairly extensive modifications to your upper receiver (These are highlighted in the photos from Prowin’s website). You can see how far you need to modify the stock receiver just to get the bolt lock function to work reliably. 

You will also have to remove a 0.1mm of depth in the front of the bolt where the rear of the router face meets the bolt body. This is hard to explain in this post but is outlined in the guide Prowin have shown on the website. (

You will also have to modify the stock bolt stop too since the dropped router face of the nozzle will hit the top of the bolt stop unless it’s modified. I have included a photo of the extent of the modification below: 

All in all, the AR9 kit takes a fair amount of mods to the gun to get it working. Can you do it? Well, that all depends if you have either a Dremel, or access to a CNC machine. I did most of the modifications to the gun with a hand file, Dremel and sandpaper. I didn’t actually modify my upper receiver, as I am a lucky owner of an Iron Airsoft F1 kit which is internally different to the stock MWS receiver. This allows me to bypass the modifications needed to a stock upper receiver. I did have to modify a portion of the adapter itself, which seems crazy but I was determined to get it to fit! This for me was much easier than having to modify the stock upper receiver to achieve full bolt lock function. 

Should you buy this kit? 

I’m trying to be fairly impartial in this kit summary since I don’t like influencing anyone’s decision into buying something that they may end up regretting. This isn’t to say that you’ll end up regretting buying the kit, but I can imagine a lot of people being put off by the number of modifications needed to get this kit 100% functioning. Yes, you can run the kit without modifying the upper, however, the bolt stop function is basically the reason why people use MWS’s. That and the incredible efficiency you get from the system, which on a positive note, you don’t lose when using Glock mags. 

The decision to purchase the kit has to be on your shoulders. Would I personally recommend it? Well, if you’re looking for a 9mm AR platform, then yes. It’s the only one that is currently on the market and once the modifications have been done, the system works incredibly well. Like I’ve mentioned above however, the main drawback of the adapter kit is the 3/4 fairly extensive mods that are needed to get the system to work. 

To summarise my review/thoughts on this kit, I think the adapter appeals to a certain type of MWS owner. I have a funny idea of why someone would buy it and the type of person you have to be in order to rationalise buying this kit. 

If you had a decent budget for a 9mm build, this would be my final suggestion. Buy the kit, but also buy another MWS to go with it. This might sound very bourgeoisie but let me explain. Most MWS owners who only own 1 MWS will for sure be put off the kit since they’ll need to permanently modify their only MWS. For those lucky enough to have 2 or 3 builds, the severity of having to permanently modify your upper receiver seems less daunting. Those who own multiple MWS’s are also obviously invested in the system enough to care about it. If you have two MWS’s, you’ve already spent over £1000 on two base guns before you’ve even purchased extra magazines or parts to modify them. The price then for someone who has spent that much on the MWS system may seem more trivial or less steep than to someone who only has one build, loves it and cringes at the idea of taking a Dremel to the internals of their beloved MWS. 

For me, it makes much more sense to dedicate a built to this 9mm kit, since you’ll be modifying that one gun to permanently host it. It won’t be a kit you swap in and out, it will just be set as your “9mm MWS”. This, of course, is only my personal opinion but was the honest mindset that I took when buying the adapter kit. I hope this write up (that stemmed from a long reply I was going to respond to @𝑵𝒆𝒐𝒏 𝑵𝒂𝒈𝒂𝒔𝒂𝒌𝒊 from the Discord group I run with) gave you an insight into how the kit is. If you have any questions for me, feel free to comment below or get in touch with me on the Discord group!


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