Mossberg 940 Pro Tactical SPX Review: Defensive Posture

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Mossberg engineered a near perfect tactical semi-auto scatter gun with the 940 Pro Tactical SPX.

From never-fail striker-fired pistols to potent AR platforms, suppressible and manageable at the shoulder, home defense options are legion. Even with these choices, the 12-gauge shotgun still has a certain daunting mystique when manning the ramparts of your property line and addressing bumps in the night.

Nothing quite says, “Get off my lawn!” more convincingly. And few companies have perfected the defensive scattergun like Mossberg.

Like a dark and avenging spirit, the company’s 500 and 590 series pump guns strike fear into the black hearts of the felonious. However, there’s a fair case to be made that Mossberg’s newest semi-auto smoothbore has the chops to hold its own versus the company’s legends. Smooth shooting, easy to manipulate and fast as AC down copper wire, the newly minted 940 Pro Tactical SPX is built for defense.

Mossberg 940 Pro Tactical SPX Specs

Gauge: 12
Action: Gas-operated semi-auto
Chamber Size: 3 inches
Barrel Length: 18.5 inches
Choke: Accu-Choke
Capacity: 7+1
Overall Length: 37 inches
LOP: Adjustable
Sights: Holosun HS407k; front fiber optic
Weight: 7.25 pounds
MSRP: $1,370

Birth of the 940

If you’re not familiar with the Mossberg 940 line of shotguns, it’s essentially a redemption story. The company’s preceding gas-operated shotgun—the 930—had all the trappings of greatness. However, it proved to require plenty of attention in the maintenance department, lest it throw in the towel and quit due to a malfunction. Bad news in field models, catastrophic in tactical variations.

The 940 action set out to remedy this issue by re-engineering several key components, with rock-solid reliability the target. As far as the ones I’ve shot since its release in 2020, Mossberg has scored a bull’s eye. The gas-gun runs like rain down a gutter and eats practically anything it’s fed.

Much of this success, not to mention dependability, of the gun has been its piston. Placed on the outside of the tubular magazine, venting gas forward and out of the way of moving parts, it runs much cleaner. Furthermore, a separate spring-loaded valve in the gas block only allows through enough gas as needed to cycle the bolt, again keeping fouling to a minimum.

Does it really cycle through upward of 1,500 shells between cleanings, per Mossberg’s marketing hype? I haven’t reached that mark personally on a single gun. But the Pro Tactical SPX and the field-grade 940 Pros I’ve shot haven’t hiccuped once through hundreds of shells.

It’s worth slipping, the piston system also makes the 940 damned versatile. From No. 8 bird to 300-grain slugs, the 940 chew through them without a hitch. This is no small feat, given that the pressure curves between those loads are worlds away from each other.

The Pro Tactical SPX gives the action plenty to munch on, as the 18.5-inch barreled shotgun has an impressive payload. Chambering 3-inch and 2 3/4-inch shells, the gun has a 6+1 and 7+1 capacity, respectively, thanks to an elongated tubular magazine. If that isn’t enough, Mossberg levels it up by including a Vang Comp 6-Shotshell Carrier Card standard, giving you a lucky 13 rounds loaded and at hand if you’re running 3-inch ammo.

Eye of the Beholder

Tactical in many circumstances simply means the gun is dressed in black and brings little practical to the table. Not the Pro Tactical SPX. Mossberg has incorporated several useful design points into the 12-gauge, making it excel at its intended defensive purpose. None more significant than its optics cut.

The model I ran was the fully stock version available with all the bells and whistles, which included a Holosun HS407K micro red dot. If you’re interested in defensive shotguns, chances are you have a streak of late adopter in you, particularly with battery-operated optics. You need to get over this because a red dot takes a defensive shotgun to an entirely different level of effectiveness.

While small, the HS407K is ideal on the SPX. Unlike on a pistol, the optic is close to the eye, thus the dot is fast and easy to acquire when shouldering the shotgun. And what it will do for your target acquisition will spin your head. Why wouldn’t you want an unfair advantage like that?

Don’t cotton to Holosun? Never fear, the Pro Tactical SPX is compatible with RMSc footprints, and it can adapt to nearly any optic thanks to its adapter plate system.

Dressed For Success

While the overall furniture on the Pro Tactical SPX is rather what you’d expect—glass-filled nylon—it has some minutiae making the gun much more user-friendly. Perhaps my favorite aspect is the fore, which Mossberg has wrapped around the top of the barrel to create a heat shield. Running the gun hard gets its barrel smoking, but this elegant feature allows you to be bold in how you handle and manipulate the gun.

Speaking of operating the SPX, Mossberg has made it simple with an oversized and knurled charging handle and bolt release. It is further enhanced with a beveled loading port and an elevator designed not to bite the thumb that feeds it. A nice touch, a brazen metallic-orange follower that leaves no doubt when the mag is empty. And the safety is in the right spot—tang—and has very aggressive texturing, making it easy to flip.

Overall, this adds up to a shotgun you evaluate and manipulate quickly and run hard.

High-Desert Showdown

A handful of other gun writers and I had the opportunity to run the 940 Pro Tactical SPX in the most fitting setting—Gunsite Academy’s defensive shotgun course. Under the tutelage of former Glendale, California, Deputy Sheriff Mario Marchman and U.S. Marine Chris Currie, we put the gun through its paces in situational training, urban tactical courses, house-clearing drill, plain-ol’ speed and accuracy tests and manipulation drills.

In three days, I did north of 500 shells worth of shooting. Adding a layer of pressure to the participants and the gas-operated Mossberg was the environment. Dry, dusty and hot, June in Arizona isn’t exactly inviting … except, perhaps, to basal cells.

The SPX performed spectacularly, particularly with the Holosun red dot. I particularly appreciated the 940’s trigger, which in tandem made double taps and target transitions lightning fast. And the gun’s rock-solid reliability shone through.

None of us did any maintenance on the guns through the course and with four shooters behind 940s, there were zero malfunctions. And this included getting the gun in the desert’s talcum-powder dust in drills meant to emulate shooting from under a vehicle.

This alone was enough to leave me impressed. However, the cherry on top was the accuracy potential—with the right load—of the SPX. This was proofed at the end of Gunsite’s infamous Urban Scrambler, a course meant to emulate an urban shooting situation and concealment. The passing shot in the course was flipping the paddle on a hostage target without maiming the hostage at 15 yards.

Three of us ran the course twice, and each person slapped the paddle and didn’t touch the hostage. We pitched Federal Power-Shok 9-pellet 00 buckshot, showing how surgical the gun could be with the right ammo.

One final point on the SPX after pitching plenty of lead, I valued the gun’s buttpad. Designed with hollow cells that collapse on recoil, it went a long way in sparing me the abuse the gun could potentially dish out.

Some Bugs

While the SPX did not malfunction on me in terms of a failure to extract, feed or the like, there were some gremlins. In particular, early on the first day of the class, the magazine occasionally prematurely released a shell onto the elevator. This did not affect how the gun cycled but did hinder topping off the magazine—a key aspect in running a defensive shotgun.

The stop was likely sticky on the fresh-from-the-box shotgun to start but seemed to work itself out through the course of 30 or so shells. From then on, the issue ceased.

Parting Shot

Protecting your property and all those who reside in it is a serious job. The 940 Pro Tactical SPX is a serious tool to accomplish this task. The 12-gauge can put hate on target, is quick to manipulate and, above all, is reliable.

Certainly, in this day and age, the smoothbore isn’t the first tool some reach for to guard against the ills of this world. But the SPX should make those folks reconsider. Mossberg hasn’t simply designed a shotgun; it’s engineered a defensive star.

Mossberg 940 Pro Tactical SPX Deals

Sportsman's Warehouse	$900
Palmetto State Armory	$1,168

Gear Notes: Holosun HS407K

Holosun has been in the red dot game for a spell now and more than understands the needs of shooters. Hence, the HS407K sight. The small and unassuming addition to a pistol—in my case, a shotgun—vastly enhances your ability not only to acquire targets, but also to hit them.

Down to basics, the HS407K is a micro-red dot primarily designed for pistols, in particular one aimed at concealed carry. Coming in at 0.95 inch in height and 1 ounce in weight, even on this demure class of handguns, the optic doesn’t take up much room. Even better, it is small enough that it won’t throw the balance of a gun off either.

Given its size, the red dot’s window is on the small side; however, crystal-clear glass and a very visible red dot still make it quick onto the target. The dot itself is 6 MOA and has 12 brightness settings, 10 of which are night vision compatible. Plus, it has 30 MOA of windage and elevation.

Additionally, the HS407K features shake-and-wake technology, a battery-saving feature I value. Quite simply, when not in use, the unit turns off, but it comes alive the moment you draw your gun or move it. Just so you know, the unit is powered off of a 1632 battery, which is side-mounted, so when you swap in a fresh cell, you don’t lose your zero.

Overall, I walked away impressed with what Holosun brought to the table with the HS407K running it on the Mossberg Pro Tactical SPX. While small, the rear mounting of the unit on the shotgun filled the eye and picked up the pace of my hits.

The red dot is available as part of a package with the fully loaded shotgun. But, from what I saw when running the SPX, I wouldn’t hesitate to stick one on a defensive pistol. MSRP: $259

Editor's Note: This article originally appeared in the November 2025 issue of Gun Digest the Magazine.

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