The Mossberg 500 series of shotguns has a long and storied history of service to both civilians and armed professionals. The Mossberg 590 and 590A1 have repeatedly been lauded as the pinnacle of pump-action fighting shotguns. The massive adoption of the platform has led to the creation of several variants over the years. Up to this point, these variants still required aftermarket conversion to function reliably with short shotgun shells. Options like Federal’s Shorty Shotshells 1¾-inch shotgun ammunition have become increasingly popular due to their ability to add capacity to pump-action shotguns. This rise in popularity triggered the release of a new 590 variant geared towards that very ammunition type.

Mossberg 590S Shockwave Battle

The Mossberg 590S was purpose-built to reliably feed both standard and short shotgun shells. This has eliminated the need for flimsy aftermarket conversions. The workhorse defensive shotgun is now available in a variety of formats, including the 20-inch full-size model and its polar opposite, the 590S Shockwave, which has a raptor grip and barrel just over 14 inches long. With a high-quality platform available in such distinct options, it begs the question, which is the more effective defensive tool?

590S Shockwave

As the shortest available version of the 590S platform, the Shockwave is ideal for extreme close-quarters defensive situations. Categorized by the ATF as a “firearm,” the Shockwave cuts a much smaller silhouette than full-size shotguns without requiring NFA paperwork. The Shockwave sports a raptor grip instead of a stock. Its barrel is just over 14 inches for enhanced maneuverability. A hand strap on the pump of the Shockwave mitigates the risk of the shooter’s hand getting in front of the reduced barrel. The 590S Shockwave packs 12-gauge power into an easily stored and easily deployed package. Lastly, the Shockwave’s ability to handle less-lethal ammunition in conjunction with its small profile makes it ideal for tactical police units and some military personnel.

While the Shockwave’s small size is its claim to fame, it is also the feature that will worry some shooters. Some worry that the smaller magazine tube will not hold enough ammunition in dire circumstances. Many assume the short barrel and lack of stock will make the gun difficult to fire with the necessary accuracy. The inclusion of the raptor grip rather than a stock does preclude the gun being fired from the shoulder. In fact, it is made to be fired from hip or chest height. Many shooters feel firing a 12-gauge firearm from these positions is not viable due to recoil. These are concerns that are worth exploring, but they are far less impactful when it comes to the 590S.

The gun has been designed to feed shorty shells reliably, which has increased the Shockwave’s utility in several ways. Making use of compact ammunition, shooters can drop a shell in the chamber and then pack the magazine tube with eight rounds of ammo, totaling nine. They can then raise the gun almost to eye level, being sure to maintain the proper distance from the grip to the face. From this position, they can better gauge where the shot will land when they fire. The reduced recoil of the 1.75-inch shell is less likely to injure the shooter than the 2.75-inch shell while still being quite lethal.

Fully Loaded 590S

Of course, if space allows, having a full-sized shotgun is going to pay dividends in a plethora of areas. Mossberg’s 590S with a 20-inch barrel gives users everything they loved with the original, now with the ability to deliver a massive load of minis – 13+1 to be exact. The longer barrel lays the foundation for an extended tube without increasing the outline of the gun and making it lengthier than it needs to be. As this gun is not built for the tightest places on earth, the manufacturer fits the 590S with conventional stock, which allows the gun to be fired from the shoulder.

With that comes the ability to safely sight down the barrel. To capitalize on that feature, our friends in Connecticut offer these clad with fully adjustable sights, or now a handy optics cut to mount your favorite electro-optic. The enhanced controllability means that there isn’t any need for a security strap, which frees up enough room for 270 degrees of M-Lok slotting. Larger platforms host accessories like lights or lasers more effectively and just plain look cool all decked out.

Head-To-Head

On the range, we put both shotguns through several tests and courses of fire. We assessed the platforms to get a feel for their strengths and weaknesses. Despite knowing the obvious difference in capacity, we elected to begin by seeing how that played out during live fire. We loaded the two Mossbergs to their respective capacities with Federal Shorty Shell #8 shot target loads. We then fired them side by side until they were empty. The five extra shots in the full size kept it shooting longer, which in a defensive scenario could mean the difference between life or death.

The nine-shot capacity of the Shockwave was impressive for the size of the platform. Moving further back from the targets, we began to see the clear advantage of the full-size 590S in this specific scenario. The lack of a stock to index with the shooter’s shoulder on the Shockwave means that the shooter is more likely to miss a target at distance. The smaller magazine tube on the Shockwave makes these misses less forgiving.

Next, we shot the two guns to see what kind of patterns they would make downrange. Set up at 12 yards, we used Federal Premium Force X2 buckshot for the test. The Shockwave 590S does not make use of adjustable chokes and features a standard cylinder bore. The full-size 590S makes use of the Accu-Choke interchangeable choke system, so for this test, we used the included cylinder choke to make the comparison as close as possible.

Patterns & Drills

In a surprising turn of events, the two guns punched very similar patterns in the paper despite the difference in their barrel lengths. Both guns managed to land four out of six 00 pellets wholly within the Alpha zone of an IPSC target. This outcome proved quite interesting, considering there was not a distinct advantage or disadvantage to the small size of the Shockwave. In the case of pattern out to standard defensive shotgun distances, the two guns are evenly matched. Shooters can be confident that their pattern with buckshot should land inside the confines of a man-sized target at 15 yards regardless of which format of 590S they opt for.

Moving on to drills, we fired the two 590S models in the confines of a hallway that we recreated on the range. Targets were dispersed in several areas outside of the hall, including hard-to-reach spots that required tight maneuvering to engage properly. By ensuring that the shooter would have to fire at some targets from compromised positions, we were able to see the clear differences between the two sizes of 590S during the drills. The Shockwave was the clear winner in the tight quarters of the barrel hallway.

The short barrel allowed it to be much more easily aimed inside the hall. It also allowed the shooter to quickly push the gun into tight openings and make shots on the partially obscured IPSC targets. The stock of the full-size 590S offered a more stable shooting platform during long strings of fire, even in compromised positions. Unfortunately, the additional time and movement needed to maneuver the gun through shooting ports and tight spaces could be enough to spell out utter doom in the right scenario.

And The Winner Is…

Throughout the course of testing, both 590S variants performed well in the arena that suited them best and performed admirably even in those scenarios that didn’t. It was clear to see that both models have a place in a shooter’s defensive tool kit. The full-size is a “ready for anything” shotgun; it thrives in situations where storage space, weight and maneuverability are less of a concern. The Shockwave is at its best when something with a small footprint that packs a solid amount of firepower is needed. It’s tailor-made to serve in defensive situations in tight quarters. When maneuverability and intuitive shooting are at the forefront of a situation, the Shockwave is a solid option. The ability of the Mossberg 590S series to reliably cycle 1.75-inch shotshells means that a shooter can go into any of the above defensive scenarios with maximum capacity and confidence. For more information, visit mossberg.com.

SPECIFICATIONS: Mossberg 590S Shockwave

• Gauge: 12 Gauge
• Barrel: 14.38 inches
• Overall Length: 26.37 inches
• Weight: 5.3 pounds
• Stock: Raptor
• Sights: Front bead
• Action: Pump action
• Finish: Matte blue
• Capacity: 8+1 (1¾-inch), 5+1 (2¾-inch), 4+1 (3-inch)
• MSRP: $662

SPECIFICATIONS: Mossberg 590S Full Size

• Gauge: 12 Gauge
• Barrel: 20 inches
• Overall Length: 41 inches
• Weight: 7.25 pounds
• Stock: Synthetic
• Sights: Ghost ring front
• Action: Pump action
• Finish: Matte blue
• Capacity: 13+1 (1¾-inch), 8+1 (2¾-inch), 7+1 (3-inch)
• MSRP: $777

This article originally appeared in the September-October 2023 issue of Tactical Life. Get your print or digital copy or subscription at OutdoorGroupStore.com.