Gun Review: ZRODelta Modulus 9mm Modular Pistol System

They tell me the ZRODelta Modulus is one firearm, but it sure feels like three. Scratch that, nine. More? The maths are hard to suss out, but with this complete Deployment Kit the configuration options are deep and wide.

So that’s it. That’s the actual gun. At least, the part our benevolent government overlords have deemed the “firearm” that must be serialized and otherwise marked. Then you add the other parts, which are available a la carte or all at once in the Baller Kit. Err, Deployment Kit:

Holy crap. This is a lot of stuff. Let’s see, there are three slides (all cut for an optic and all with a blanking plate), barrels, and recoil spring assemblies. Three Picatinny rail dust covers, three backstraps, two frontstraps, three magazine wells, two magazines, and the grip module.

Oh! And all of the tools you’ll need to swap all of those parts around. And some spare hardware to replace the screws you drop through the floor register.

I know what you’re thinking. No, the USB flash drive doesn’t plug into the Modulus anywhere. Unfortunately. (please direct all Big Brother-related feedback to Dan). It contains the owner’s manual and…well…heck if I know, who reads owner’s manuals?

Thankfully, it’s all pretty darn self-explanatory.

With one hex wrench and one Torx wrench, the user can swap between all three magazine wells, all of the front- and backstraps, and all three accessory rails and, therefore, all three slide lengths. Quickly and easily.

The short-and-skinny magwell seen above provides a carry-sized grip height, but in 20 seconds . . .

You can move over to a full-length grip with a massively-flared, competition-style magwell.

Every part of the ZRODelta Modulus (or MOD•U•LUS per the logo) is extremely precisely machined. The magazine wells even snap into place via the tab visible at rear just in front of the bolt hole. Slide the magwell into place and then press and CLICK, the tab snaps over a corresponding rib inside of the grip frame, holding everything in place as you insert and snug the retaining screw. Nice.

At about twice the width of the magazine, this funnel is hard to miss.

Each magazine well serves a different use and changes the height and feel of the Modulus. For instance, while retaining the extended length slide . . .

The flared magwell completes the competition look, feel, and function.

The short magwell makes for a drastic change. Clearly much more than just flare diameter, the magwells really make a difference in grip height. With the shorty module on, the Modulus is G19-ish compact in size and ready for concealed carry.

The medium magwell is, then, somewhere in the middle. It’s basically a full-size (G17-ish) height, but without the skirt of the flared magwell unit.

Though, as you can see above, the medium magwell does provide more of a funnel than the shorty option. It’s wild how much of a difference these make with one bolt and 20 seconds.

This has much to do with the design of the grip module, which is kept short and slim in order to let the magazine wells, front- and backstraps, and accessory rails have a big effect on the end product. That is, the specific Modulus configuration created by the owner.

Frontstraps, whether flat or finger-grooved, are machined with what is effectively a T-slot and they slide up a matching rail on the grip module. They’re then held in place by the magazine well of your choice.

Backstraps are a similar story, though a little more involved. They slide into grooves at the rear of the serialized chassis and then a cross pin is pushed through.

This can be done by hand or with any of the tools, as it slides in easily. Then, when the magazine well bolt is tightened (it actually threads into the backstrap rather than into the grip module) everything is thoroughly snugged up and that cross pin isn’t going anywhere.

Inside the backstraps was the only place in any component of the Deployment Kit where I found unsightly machine marks (up at the inside top they all have some aggressive step and tool path marks). In fact, machining quality overall is incredible. Truly top notch.

And the fit between all of the components is fairly incredible as well. While, close up, the gun may look like it might not feel…contiguous?…like one solid unit?…like it’s full of seams and gaps and maybe that it would wiggle or shift a little?…this is absolutely, 100 percent not the case.

Those lines look like lines but they don’t feel like them. If the Modulus were machined from a single chunk of aluminum, it would feel no different in the hand. Including while shooting; it’s rock solid.

Unfortunately, because the fit is so dang precise and the machining so darn good, I’m not confident that much of the aftermarket will be able to whip up bolt-on components of its own that work as seamlessly and solidly on the Modulus as the factory parts. And obviously it would be very cool if a bunch of companies jumped onto it and started offering their own pieces for this MOD•U•LUS puzzle.

Like frontstraps, including in different colors and materials. Right? Limitless opportunities here to bolt cool stuff to this chassis, whether it’s parts that fit on the existing grip module or literally creating an entirely new gun — doesn’t even have to remain a pistol — that starts with nothing more than the serialized chassis.

After shooting with both, I preferred the frontstrap with the finger grooves. Though usually I view finger grooves as a risk for the gun manufacturer since they won’t work with all hand sizes, the ZRODelta Modulus’ grooves worked perfectly for me and, if they hadn’t, it’s an extremely fast and easy swap over to the flat flavor.

I shot the Modulus in its Compact format. It shot great.

I shot the Modulus in its Duty format. It shot great.

I shot the Modulus in its Extended format with a U.S. Optics red dot mounted up. It shot great.

I even configured the Modulus with Extended slide on Compact frame and vice versa, straight-ish backstrap (my favorite — it changes the effective grip angle to make it less swept and closer to 1911 than GLOCK), extended beavertail backstrap, both frontstraps, all magwells, etc etc. It all shot great.

And it was a lot of fun. There was coffee and hanging out at The Range at Austin and lots of Armscor ammo (and other ammo) turned into noise and holes in paper.

Overall I think it’s fair to say that the Modulus 9mm shoots more or less like a well-tuned GLOCK, but feels better in the hand. Partially that’s due to better ergos and partially to the stout, strong feel of a metal frame, plus nice touches like the aggressively undercut trigger guard and high beavertail.

But the timing of it and the geometry of the locking system, the trigger, the general shape, and more are all essence of GLOCK. Which is no surprise, really, as the Modulus 9mm is Gen3 GLOCK components compatible. Not everything, of course, but triggers, slides, barrels, sights, magazines, extractors, firing pins, takedown levers, and more are all Gen3 GLOCK footprint.

Chris’ tender hands found the vertical serrations on the backstrap — specifically, the outermost one on each side — too sharp. They rubbed him the wrong way. If I twist my grip I can absolutely see exactly what he’s talking about, but it didn’t bother me while shooting like it did him.

The Modulus feels familiar in the hand for a GLOCK shooter, but at the same time better, curvier, more ergonomic, and more substantial. Not in weight, but in feel or texture. That aluminum versus plastic thing.

From U.S. Optics’ much more affordable, overseas-manufactured line dubbed USO, comes the DRS (Dynamic Reflex Sight) seen above.

I haven’t tested it in enough scenarios or knocked it around enough to review it, but it was a solid performer at the range. The dot was clean and precise at the lower brightness settings appropriate for the indoor lighting and then grew a bit in size and edge fuzziness as it went up to quite-impressively-bright-indeed levels.

I didn’t bother sighting in the DRS (so don’t mind the off-center groups), but that nice red dot still came in handy for showing that the Modulus is a straight shooter at 25 yards. It won’t set records or anything, but for a GLOCK-compatible design shooting inexpensive ammo it’s a solid performer.

Without a doubt I put up better groups at 25 yards with a red dot than with iron sights. My eyesight ain’t what it used to be (in fact, I usually shoot test groups with my stronger, not-badly-in-need-of-vision-correction, non-dominant eye).

And, while I absolutely love an all-black, serrated rear sight like what’s included on the Modulus, I need something happening up front to help me out. A white dot, a brass bead, a fiber optic, whatever. The black-on-black thing is acceptable for slow, precision stuff but it slows me down for everything else.

Though the ZRODelta Modulus is compatible with Gen3 GLOCK components, it clearly is not a GLOCK. Nor is it made with what are generally considered to be GLOCK’s somewhat loose clearances.

Dropping in an aftermarket threaded barrel, it fit great but also ever so slightly more snugly than in a GLOCK brand GLOCK slide. I could just barely feel it in the lockup, popping into place with the slightest of snicks rather than just plopping in there all plenty-of-room-to-spare like.

The on-the-range result of this was that it ran flawlessly with nothing on the muzzle regardless of ammo choice, ran flawlessly with a suppressor when shooting full-power ammo (e.g. 147 grain HST, defense-loaded 115 grain hollow points, and 124 grain NATO-spec stuff), and ejected very weakly and sometimes not completely with a suppressor while shooting range-power, subsonic ammo.

It was close enough that I think with some lube on the barrel hood and some break-in it would become reliable in that third scenario, too. But for me, on the outing I shot the Modulus suppressed, it wasn’t reliable with range fodder subs.

So what do you think? Is this nuts or what? How many possible configurations can you count? I mean, someone [else] should legitimately do the math, right?

I suppose as the big config changes go, there are three slide lengths and three frame options, all of which can be mix-matched as you please. So…nine different, optics-ready guns? When I put it that way, the Deployment Kit’s $2,799 seems like a screaming deal.

Put another way, it’s more than a GLOCK. But in a land where a ZEV or an Agency Arms “Gucci GLOCK” can run up to $2,000, the cost of this gigantic ZRODelta kit isn’t at all out of bounds. And it’s a great shooting pistol in every configuration.

Of course, if you don’t envision taking full advantage of the Modulus’ extreme modularity, ZRODelta sells full Moduluses in each of the three primary configurations: Compact, Duty, and Extended. Decidedly less cool than this entire kit, but still a very sweet gun with the option to add component parts later.

While I’m not sure I could bring myself to swing for the Deployment Kit, I could see purchasing a Duty pistol plus the Compact magazine well a la carte. The other stuff is cool, but would I really put it to use? Perhaps I’m not baller enough, though if I were I’d for sure display the Modulus Deployment Kit in its case (see lead photo) under glass in a nice frame and hang it on my wall.

Specifications: ZRODelta Modulus 9mm

Caliber: 9×19
Capacity: 17+1
Barrel Lengths: 4-inch, 4.5-inch, and 5.25-inch
Slide Lengths: 6.75-inch, 7.5-inch, and 8-inch
Trigger: 5.5 lbs
Weight: 23.5 ounces to 27.3 ounces (complete Compact to complete Extended)
MSRP: $2,799 for complete Deployment Kit. $1,299, $1,349, and $1,400 for Compact, Duty, and Extended pistols, respectively.

RATINGS (out of five stars):

Style and Appearance  * * * * *
Dude, I like it. Every configuration of it. And the cuts in the extended length slide look great.

Ergonomics  * * * *
Hey I’ve had better, but it sure one-ups a GLOCK.

Customization  * * * * *
Um, yeah, the Modulus sets the new bar for what five stars in this category means. Not only does it do the Erector Set on steroids thing it does, but it’s compatible with one of the most prevalent aftermarket gun parts segments in the country: Gen3 GLOCK parts.

Accuracy  * * * 
Didn’t delight or disappoint.

Overall  * * * *
The ZRODelta Modulus is definitely rad and probably groundbreaking. It’s an incredible feat of engineering with machining, fit, and finish quality through the roof. I even think it’s priced pretty freakin’ well for what it is. But I can’t quite bring myself to give it five stars — we’ll call it a very strong four, though. At least for the Deployment Kit. If I’m honest I just don’t envision users taking advantage of the modularity. We like to think we will, and then we find our favorite configuration and everything else collects dust. In the Modulus I could see running the Duty-length slide all the time and swapping between the Compact and Duty magazine wells. But that’s it. $1,365 and I’m there. The rest is just baller status. Not that there’s anything wrong with that. Now, if the aftermarket jumps in and all sorts of crazy bolt-ons become available for the Modulus chassis, I may have to go back to the calculator and add that fifth star. Could be the hot new ticket.