Gear/Gun Review: MechTech C.C.U. (Carbine Conversion Unit)


Do you own a GLOCK? A 1911? Well if you do, MechTech Systems of Kalispell, Montana has a C.C.U. for you. That’s Carbine Conversion Unit and it does just that — converts your pistol into a carbine with an ATF-legal 16″ barrel, a stock, and rail space for optics and accessories. It isn’t a firearm, which means it can ship right to your door, all without changing the Federal classification of your handgun. Sounds great on paper, but does it actually work? . . .

Spoiler alert: Yes, it works. Wonderfully. Quality, accuracy, reliability…all awesome. You’ll still find a full review below, but the dozen-word version is that any GLOCK or 1911 owner should have at least one MechTech CCU in their stable.



How It Works

MechTech’s CCU is a new “upper” for your pistol. In the case of GLOCK, this means small frame (9mm, .40 S&W, or .357 Sig) or large frame (10mm or .45 ACP) — click here for the list of compatible frames. Perhaps the coolest benefit here is that the small or large GLOCK frames are identical regardless of caliber, so you can get a CCU in any or all calibers that match your frame. In my case, I chose to use my G20SF and MechTech was kind enough to loan me both a 10mm and a .45 ACP CCU. The 1911 offers quite a lot of same-frame caliber swapping ability as well, so your .45 may work with a 1911 CCU in 9mm, .38 Super, .40 S&W, 10mm, .45 ACP, or .460 Rowland. EDIT: MechTech doesn’t cut chambers for .45 GAP, and due to low demand intends to scale back its available 1911 calibers to .45 ACP, .45 Super, and .460 Rowland.

Field strip that GLOCK or 1911 and the frame is ready to install. In the case of a GLOCK, you’ll need to pop the MechTech Feed Ramp onto the locking block.


During assembly it’s held in place by a small magnet, and once the frame and CCU are joined it’s physically pinned in by the CCU’s barrel.


Lock the CCU’s bolt back by pushing the charging knob into the cutouts in the channel:


Line up the slide rails with the notches in the CCU’s body:


Finally, push the frame forwards until it slightly compresses the rubber bump stop at front and the factory locking tabs click up into place, locking the frame to the CCU in a very factory GLOCK-like manner.


Et voila, you have a carbine!

Functionally, the MechTech CCU is a straight blowback-operated unit like nearly all pistol caliber carbines. It utilizes a heavy bolt to slightly retard and to control rearward movement, and it also has a nice, thick, rubber recoil/bolt stop at the rear.


Extractor, ejector, and firing pin are all contained in the CCU, of course.


In this case it is legal to convert your pistol into a rifle configuration and then back into a pistol configuration. The BATFE ruled:

Held further, a firearm, as defined by 26 U.S.C. 5845(a)(3) and (a)(4), is not made
when a pistol is attached to a part or parts designed to convert the pistol into a rifle with a
barrel of 16 inches or more in length, and the parts are later unassembled in a configuration
not regulated under the NFA (e.g., as a pistol).

While it’s specifically illegal to turn a rifle into a pistol, in the case of the CCU the “firearm” part of the system is a pistol and was manufactured as a pistol. Connecting it to the CCU isn’t altering the design of the pistol itself at all, it’s only temporarily switching to rifle configuration via an attachment. No permanent change or redesign is made. ATF ruling is here and further explanation is on MechTech’s forum here.


As near as I can tell, the body of the MechTech CCU is a powder-coated piece of conduit or other pipe. It’s basically what I was expecting of the entire build of this thing, but all of the interior components pleasantly surprised me with materials quality and machining quality above and beyond what I thought I’d find.


Most of the components that are machined by MechTech and added inside of that pipe body are made of high polished steel, including the entire bolt channel insert, the bolt, etc. The heavy-profile, button-rifled barrel is stainless steel. The machining is really top notch, and I’ve done a disservice to MechTech by taking my photos after shooting and dirtying up the CCUs.


I was truly very pleased and a bit surprised to see and feel the quality going on inside of the CCU here.


The barrel alone looks like something that would cost a healthy portion of the CCU’s entire MSRP were it an aftermarket AR-15 upgrade part.


Customize This

As you can see in the lead photos, there are different stocks and different rails on each of my CCUs. One has a flash hider and one does not. MechTech offers a whole bunch of custom configuration options and accessories that can be added to the base model CCU. Primarily, you’ll want to choose your accessory rail configuration and your butt stock. Although I really dig the telescoping wire stock with nice rubber butt pad that’s on my 10mm CCU, the option to order it with an M4 buffer tube adapter probably wins out as it opens up near-infinite options for any stock that fits an AR-15.

I do like the “Mini Rail Kit” that’s on the 10mm one, as it provides a full-length top rail with a comfortable grip on bottom plus some short rail sections out front, while weighing less than the “Quad Rail” on the .45 ACP example. When I order up my own, I may go for the standard config (6″ rail section above the action) plus the “Mini Quad” out front to leave my options open but further reduce weight.


Unfortunately, MechTech does not offer barrel threading (muzzle devices from them are pressed on). Too many size and pitch possibilities to tool up to accommodate, basically. I do wish they’d consider threading for the three most popular pistol sizes, though: 1/2×28, 16×1 LH, and 0.578×28. This would cover most or all of the calibers that can be shot through the CCU, and definitely covers the two subsonic calibers (9×19 and .45 ACP). Purchasers would pay for this service. I know I would. Many do it later, of course, and simply take their CCUs to a local gunsmith or machine shop.


So there’s really no “field stripping” of the CCU. For the most part, you’re expected to clean what you can access with the bolt forwards and/or locked to the rear. This does give you the ability to clean the barrel and clean and lube most of the moving parts and friction surfaces. As it’s a straight blowback action, it doesn’t really require the level of cleaning that most firearms with locking mechanisms are going to need.

That said, it would be nice if a simple field strip were possible. When you decide you want to take the parts out, you have to truly disassemble the CCU and it isn’t quick or something you could do “in the field” without tools and some time.


Although all CCUs in all calibers receive 1:16″ twist rifling, I found accuracy to be exemplary in both the slow-moving .45 ACP and screamingly velocious 10mm (more on 10mm velocity out of a 16″ bbl soon). Where I set up in the woods I was only able to stretch out to 50 yards, but I hit my FBI Q target, which was at a 45* oblique angle and therefore even smaller than its full 12″ width, with boring ease and regularity from standing.

On a sandbag rest at the indoor range, 5-shot groups from the .45 ACP at 25 yards looked like this:


I did not officially accuracy test the 10mm CCU, but thought it was shooting just a tad tighter based on my time in the woods. The one 5-shot group I managed to put on paper was ruined by a shooter-induced flyer:


10mm from a 16.25″ Barrel

Thanks to one trip to the woods without a 9-volt battery for the chronograph, two with lousy weather — skies so dark my chronograph wouldn’t read — plus one failed attempt to get chronograph readings under the fluorescent lights at the indoor range, and then the pending arrival (and then arrival) of the wife’s and my second little girl when the weather finally took a turn for sunny skies, I was totally unable to get chronograph readings for over a month. This simply would not do, as I know 10mm gains substantial velocity out of a longer barrel and I just had to quantify that for myself and for y’all.

In a moment of brilliance (I have low standards for myself), I hit up ShootingTheBull410, who arguably has the very best ballistics testing channel on YouTube. Of course he’d like to borrow the 10mm CCU for some ballistics testing! With MechTech’s blessing, I shipped it off to STB410 along with a sampling of ammo and my G20 “upper” so he could get factory velocity readings with the use of his G21 frame. Keep an eye on TTAG here and on STB’s channel in the future if you’re as excited to see gel block testing of 10mm through the MechTech CCU as I am. For the time being, here’s what STB saw for velocity gains:

Factory Barrel (4.6″ bbl) Averages:

Buffalo Bore 180 grn JHP: 1,292 fps — 667 ft-lbs
Underwood 220 grn Hard Cast Lead (my woods carry load): 1,134 fps — 628 ft-lbs
DoubleTap 165 grn Bonded JHP: 1,301 fps — 620 ft-lbs

MechTech Upper (16.25″ bbl) Averages:

Buffalo Bore 180 grn JHP: 1,603 fps — 1,026.8 ft-lbs
Underwood 220 grn HCLFP: 1,359 fps — 902 ft-lbs
DoubleTap 165 grn JHP: 1,630 fps — 973.2 ft-lbs
Bonus: .40 S&W Liberty “HALO Point” (now “Civil Defense”) 60 grn HP: 2,569 fps — 879 ft-lbs

Average velocity increase (not including the Liberty load) was 288.3 fps and the average kinetic energy increase was a whopping 329 ft-lbs (51.54% increase). Probably time to go hog hunting.

On The Range

MechTech’s CCU is a joy to shoot. It’s everything you’d want from a pistol caliber carbine, if a touch on the heavy side — balanced towards the muzzle end. Recoil is very tame and ergonomics are pretty solid. The pistol locks in securely and the whole assembled unit feels like it was designed this way rather than assembled out of two halves from two companies.

Feeding from the magazine is perfect. Walking the bolt forwards as slowly as possible results in rounds stripped out of the mag and aimed just right so they slide into the chamber and up the bolt face with a bare minimum of resistance — better than in most pistols. Firing and ejection was also flawless, with perfectly-dented primers and consistent ejection across the board. I suffered zero stoppages of any sort in either caliber, which included shooting in heavy rain on one trip and in below-freezing temps on another.


A straight blowback action wouldn’t typically be recommended for high-pressure calibers, but all of my 10mm brass looked flawless, to include a couple of mags worth of two different Underwood loads (note: MechTech specifically advises not to shoot Underwood, as it’s the only brand of ammo that has resulted in blown cases in a CCU) and one mag of Buffalo Bore hollow points. In fact, the brass looked much better than when shot through the factory GLOCK barrel. No GLOCK “smile” at all, thanks to better chamber support. It seems that the bolt is definitely heavy enough to allow pressures to drop before the case backs out of the chamber.

Much to the dismay of the TTAG hall monitors and other safety 1st, 2nd, and 3rd types, I’m one of those guys who shoots tons of .40 S&W through a completely factory GLOCK 20. If anyone cares to know why I believe it to be safe — safer, even, than shooting 10mm through a 10mm GLOCK or .40 through a .40 — I’ll create a separate article on the topic. If you would, please save your derisive comments or friendly debate or questions on the subject for that article (just let me know here if that’s of interest or you can e-mail me at GunsAndGearEJ20 [ at) gmail if you want to see it but don’t want to derail the comments here away from the CCU itself). Anyway… after inspection I chose to run some .40 S&W through the 10mm CCU and it functioned completely flawlessly and the brass looked perfect. Once again, it looked better than .40 S&W brass fired through a GLOCK (whether through a .40 barrel or a 10mm barrel) due to the improved chamber support.


The appeal of owning a carbine and a pistol that not only shoot the same caliber but accept the same magazines has always been strong for me. I love the idea of a “bug out bag” outfitted ‘thusly.’ MechTech’s CCU really takes that one step further by providing a carbine that isn’t even a firearm, which means it ships right to your door with no FFL and it’s particularly sleek since it has no firing control, frame, or grip components. The ability to use one frame to shoot a handful of calibers is another nice bonus.

It’s mighty potent and accurate in 10mm, but I’m not going to hunt with it so when I go to purchase one of these for myself I’m going to stick with a subsonic caliber for shooting suppressed. As I don’t own a .45 can, it’ll be 9mm. I may pick up a double-stack 9mm 1911 for the job. As durable and versatile as a GLOCK is, I think I want this bad boy for a 1911 due to the quality of the trigger pull and the option for a manual safety. With all of this taken into account, a double-stack 1911 is likely my ideal setup. That said, I don’t own a small frame GLOCK at the moment and if I already had one that would likely change the math.

Every GLOCK or 1911 owner should have a MechTech CCU to go with it. Simple as that. It’s a disservice to yourself not to.

Specifications: MechTech CCU

Caliber: Many available
Capacity: Same as your pistol can accept
Barrel length: 16.25″
Overall length: Varies from under 24″ to over 33″ depending on stock choice and adjustment setting
Weight: 5.3 lbs in lightest, “basic” configuration
MSRP: $399.95 in “basic” configuration plus any additional accessories

Ratings (Out of Five Stars): 

Accuracy: * * * * 
It’s no bench rest rifle but for a relatively inexpensive carbine conversion adapter, it’s really excellent.

Ergonomics: * * * * 
Your pistol has some bearing here. The GLOCK part still feels like a GLOCK. Otherwise, the frame-to-CCU interface, angle, and location feel just right. Everything else feels like it should, and the option to use any AR-15 butt stock really opens things up for ergonomics. I’m taking off one star just because it’s a bit nose heavy.

Reliability: * * * * *
Flawless for me, and the straight blowback action should run just about anything without stopping.

Customize This: * * * * *
Tons of factory options for rail configurations, accessories, butt stocks, and more. With the AR-15 buffer tube adapter, the sky’s the limit there. You’ll have to get it threaded for muzzle attachments after you receive it, though.

Overall: * * * * *
Awesome. The versatility and quality you get starting at $399.95 is worth every penny.