MCK Micro Conversion Kit for Glocks, by Pat Cascio

I’ve always been of the mind that the less you do to a firearm, in the way of customizing it, the better off you’ll be. I’ve come to this way thinking for a number of reasons, first and foremost is the problem of liability. So I don’t like to do a lot of custom work on a firearm for my own use.

The grand old 1911 is the most customized handgun in the world – has been for a lot of years. I used to do a lot of custom work on 1911s – not only for myself, but for some of my customers, when I was doing gunsmithing work. Now, with that said, I’ve seen this happen in court, and I’ve read about it numerous times. If you are involved in a shooting, and you used a customized firearms, the prosecuting lawyer will rake you over the coals, with questions like: “isn’t a factory gun good enough for you, but you had to have custom work done on it, so it’s more deadly?” “Why did you put a hair-trigger on your gun, so you could shoot people faster?” How about handloaded ammo? ”Doesn’t factory ammunition kill good enough for you, that you had to reload your own ammo, making it more deadly?” These are just a few of the things you might face if you shoot someone. So, I keep “customizing” to the bare minimum these days.

The Glock handguns are the second most popular firearm when it comes to customizing. There are all manner of simple drop-in parts you can install yourself on a Glock. I prefer night sights on my Glocks – some come with them, and some don’t. The reason for night sights is because I don’t want to purposely shoot at a person that might not be the intended target. Secondly, I also like the fiber optic sights, those really allow you to see the sights so you can better hit what you are aiming at. Okay, so far, so good – nothing much a lawyer can tear you apart for. I’ve installed some lighter trigger (pulls) on some Glocks over the years. However when it comes down to it, I don’t do that any longer – I don’t want to be accused of having a “hair-trigger” on my self-defense handgun. I think, with a little bit of practice, anyone can master the “mushy” trigger pull on a Glock, no need to replace the factory trigger.

So, this is why I prefer, for the most part, to keep most of my handguns “as-is” from the factory, I don’t need to be questioned in a court of law, as to why I changed something on a self-defense firearm. Now with that said, there are some “customized” parts for a Glock, that I think are worth looking at. I don’t mind an extended slide release in the least. And, installing some after-market rubber slip-on grips – not a big deal, either. But today, we’re looking at a Glock accessory that is fairly new and worth checking out, the Micro Conversion Kit from Roni.  It is being sold all over the place these days, at some great prices, too.  The original Roni kit was just “okay” but it was pretty spendy, and it just wasn’t “right” to my way of thinking. But now they have improved on it, with this newest version.

So, what is a Micro Conversion Kit for a Glock? Well, in a nutshell, it is a device that turns your Glock into something akin to a short-barreled rifle – but not really. This is hard to explain, but let’s see if I can do it. The MCK is a polymer device that allows you to insert your Glock handgun into it – and it latches on to the front Picatinny rail, and on the rear, so that locks the Glock into it, solidly. Takes just a few seconds to do, and many police departments are buying the MCK for their officers, who might have to do a building search or go into a hostage situation, because it makes the Glock more accurate and it locks solidly into your shoulder – even though it has an “arm brace” on it – that the BATFE now says you can shoulder.

Once you insert the front of you Glock into the MCK, you then lock the rear of the slide into some grasping grooves, that have a charging handle on it, and you can then chamber a round using either side of the charging handle. It works just that easy.

You can access the slide release/stop as you always could on your standard Glock.  (I should note here that the early Roni model didn’t allow that, so you had a bit of a difficult time releasing the slide once it locked open, you had to remove the empty magazine, and they pull back on the ambidextrous charging handle to close the slide on another loaded magazine.)  With this new model you can also access the magazine release, just as you normally would.

Picatinny Versatility

The MCK has a flat top Picatinny rail, so you can install flip-up/down sights on it, or even a red dot sight for fast target acquisition. I installed a set of AR-15 flip-up/down sights on my sample MCK. This only took a couple of minutes to do. I plan on getting a nice red dot sight to put on the Picatinny rail, so that the sights can co-witness through the red dot sight.

Another really nice feature is that the arm brace folds to the side, to the right side of the Glock. However, be advised you can not fire the MCK with the arm brace folded to the side. I suspect that this was a BATFE requirement.

My sample MCK came set-up to take a Glock 19. However it can be adjusted in a minute of two, to take a full-sized Glock 17 – or a Glock 22 or 23 – and several other versions. They are also now producing the MCK that will take .45 ACP and 10mm sized handguns. Make sure you check at to be sure your Glock model will fit. I purchased my MCK from the Glock Store and couldn’t be happier. They are great people to do business with and if you have any questions at all, about any Glock, they will have the answer. Right now, the MCK is being discounted all over the Internet, so check around for the best price before you purchase one from any source.

It Holds a Spare Mag

Now, if you are on the receiving end of the MCK, with your Glock inserted into it, the “barrel” of the MCK looks huge. It looks like you are on the wrong end of a 10 Gauge shotgun – it is intimidatingly huge – however it really is not a barrel, it just looks like one. And, below that is a polymer piece that you can pull out, and insert a flashlight into it. And, if that’s not enough, there is a storage compartment for a spare magazine, right in front of the magazine you have inserted into your Glock. For the ultimate home defense set-up, you can have a 33-round  Glock 9mm magazine in the pistol mag well, and right in front of it, another loaded 33-round magazine that you can quickly load into the Glock, if you used those first 33 rounds. And, there are two Picatinny rails on either side of the front grip area, where you can install a laser or light. So we are talking ultimate home self-defense handguns set-up. The forward horizontal grip area is designed so that your index finger and middle finger ride in there nicely, away from the barrel. You certainly don’t want to have your finger wander in front of the barrel when you are firing.

Very simple operation for the MCK: Insert your loaded magazine into your Glock, and pull back on the charging handle, bring the entire set-up to your shoulder, and start firing. The arm brace is a really nice one – longer than the one on the original Roni and you have the gun locked into your shoulder, as well as gripping it with your off-hand – it is a rock-solid set-up, and hitting targets out to 100 yards is very easy.

Our Shooting Tests

As usual, I had no lack of volunteer shooters for my testing of the MCK and my Glock 19, Gen 4 – in all, we fired more than 1,000-rds of 9mm ammo – all from Black Hills Ammunition, I had a wide variety of ammo, from 115-gr FMJ, to their 100-gr HoneyBadger all-copper fluted bullets that are wicked and +P rated. I also had their 124-gr JHP +P, as well as 115-gr JHP – not one failure to feed, function or eject.  Then again, I had already put a lot of rounds through this Glock, so I knew it was reliable to start with.

Accuracy testing was done at 25-yards, standing, with the arm brace locked into the shoulder…and I could easily get 1-inch groups if I was on my game – with all the ammo. The biggest “problem” we encountered was the repeated “hand me a couple more boxes of ammo…” from the shooters.

By the way the MCK also comes in versions to fit the S&W  M&P 2.0 version, as well as the SIG-Sauer P320. However, my P320 won’t work in an MCK because it has a red dot sight on the slide – so, once again, check first to make sure your gun will fit in an MCK.

As already mentioned, I see the Glock MCK set-up as the ultimate home defense gun/accessory. And it would also make one heck of a car gun – very easy to shoot while seated in your vehicle.  Check around for the best prices you can find. The retail on the MCK is $250 – but you can find them for less – a lot less, if you really shop the ‘net. I plan on getting another MCK for my Glock .40 23 and 22 models, as funds permit.  Check one out.


  1. The GlockStore has this NOTICE: “The MCK Stabilizer is not legal for sale in California. Please consult all applicable laws in your state before purchasing.”

    Survivalblog has information about relocating within the USA. = “The American Redoubt — Move to the Mountain States.”

    The MCK Stabilizer retails at a very affordable price.

  2. A shell for a pistol seems like a plausible alternative in certain situations. I still think having a pistol caliber carbine is a better compromise (if I need more than just a pistol in a gunfight, I’d rather have my MBR or at least a shotgun). My Keltec sub 2000 uses the same mags my Glock 22 does. It stows well in a briefcase, and can be equipped with sights when deployed that make it a 100 yard shooter fairly well. I don’t like that it folds over the top of itself, requiring that I remove and reinstall the “other than factory” sights if I want to use it at extended range, but it is a compromise I have learned to live with. I wouldn’t turn my nose up at any advantage, so the MCK seems to be worth the investment if you have the need. If I am going to carry more than just my pistol and I need something easy to stow, the Keltec is my go-to. I bought mine NIB for $300 about a decade ago, and it is still performing as expected.

  3. I always love Pat’s reviews. He has plenty of experience to form solid opinions. I would just say that the item does not make the Glock more accurate, but rather helps the user exploit the inherent accuracy in the pistol more fully.
    Sometimes, one must use a handgun for home defense rather than something better. Just remember that no matter what you attach to your pistol, it’s still just a pistol, and they are not particularly decisive in ending confrontations (compared to say, a shotgun or centerfire rifle). There are many officer-involved shootings to document dismal failures associated with pistol and SMG rounds.
    For my own money, anything with nearly the bulk of a rifle for serious purposes will BE a rifle (or shotgun).
    As a recreational toy, they look like a lot of fun!

  4. The old version had a trigger cover. This newer version doesn’t have a trigger cover, and Glocks don’t have a safety. Therefore, carrying with a round in the chamber is very dangerous, and putting it down or picking it up could very easily result in a negligent discharge. I could have had one at 50% of the sales price, but passed for safety reasons.

  5. I’ve had one of the older versions for quite some time, and tested it extensively with seveal PD’s I train. It is a niche tool, but serves very well in a couple of areas. I highly suggest them for school resource officers, plain clothes officers, or admin police officers who don’t have long guns in reach. Also viable for a get home bag when your edc pistol fits the chassis. Without a gun installed, it’s just a hunk of plastic that can be left unlocked in a desk drawer, vehicle, etc. During a critical incident, your edc can be locked in the chassis in under 5 seconds. And yes … zero is repeatable with a red dot. I’ve found this tool increases the effective range of a glock to around 100 yards, and allows average police officers (not high end shooters) to make consistent head shots to 30+ yards. Even in use with simmunition guns, effectiveness was greatly increased over the pistol alone. All of this at minimal weight. This is a cost effective, light weight chassis that brings out the most of the pistol you already have, but is not intended to replace a rifle. With a white light on the side rail and a single point sling on the chassis, it really is a unique tool that is very effective.

  6. Pat,
    Any idea if the MCK will work with a SIG P226/MK-25 or a P220? I know Sig has the same type of product (or did) called the ACP/Adaptive Carbine Platform, but wondered if one was available from MCK.

  7. Ehhhhkkkkk, there’s so much wrong with this article I don’t know where to start. So I guess I’ll just start from the top. The argument that you will be raked over the coals and prosecuted for using a custom gun or reloads is old mythical bs. Any halfway decent defense attorney can squelch that argument in a heartbeat. Of course if someone was dumb enough to have literally a hair trigger or turn their gun into a full auto, that’s a different story. But customizing your weapon to improve the trigger and make the gun more accurate and reliable by changing out some parts is not something to worry about if you should shoot someone in a justified shooting.
    The same can be said of reloads. I personally reload and I will carry my reloads without hesitation because I know how accurate and reliable they are. “No your honor, the perp didn’t die because my reloads were more deadly than factory ammo, it might have more to do with the 5 round burst he got to the face, in which if I was shooting a .22 the outcome would be the same”.
    Night sights. Night sights do NOT help to identify your target, in any way. The author states he likes them because he doesn’t want to shoot at a person that isn’t the intended target. If that’s the case get a weapon mounted light, not night sights. Again, they do not help to identify the target in any way.
    Fiber optic sights…are useless in low light/no light. Not to mention, somewhat delicate. They’re great for competition shooting because in daylight the fiber tube really lights up. However, I’ve shot in competitions where the tube broke and fell out. I don’t use them on any fighting pistol.
    There is no need to settle for a “mushy” trigger. Doing a custom trigger job on a Glock consists of not necessarily making the trigger lighter, but making it cleaner. Only a fool would carry a defensive piece with a literal hair trigger. A simple trigger pull gauge would shut up any over zealous prosecutor. A 4 pound pull is a 4pound pull. If the take up is smooth, up to a pronounced wall, then a clean crisp break, it might feel lighter, but the scale doesn’t lie.
    The roni kits, in my not so humble opinion, are gimmicky. Substandard fighting gear. However, the author is worried about putting in an aftermarket trigger but wants to run a stocked/braced pistol with 33 round mags. A weapon that the damn atf can’t make up their minds on whether or not it’s legal to shoulder this week. Not to mention vertical fore grips are illegal on pistols without a stamp and I could see a prosecutor going after you for breaking nfa laws.
    Me personally, I don’t see the need for a weapon like this. I would rather a 7-8” barrel AR 9 that takes Glock mags. This contraption might help you shoot a little more accurate because you can get 4 points of contact on it as opposed to the 2 you have on a pistol. I don’t think the juice is worth the squeeze because while you might get a negligible increase in accuracy, you not gaining anything on velocity while handling a larger package than just the pistol. An AR 9 with a 7-8” barrel will significantly bump up your velocity AND accuracy. I prefer 7-8” barrels on the AR9 because if I’m gonna carry or use anything bigger like 10.5” and longer, I’m gonna have a rifle caliber. And anything smaller, I’ll just carry the pistol.
    For me, these things just make no sense. YMMV.

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