How Good Can The Mossberg 590 Shockwave Be?

How Good Can The Mossberg 590 Shockwave Be?
How Good Can The Mossberg 590 Shockwave Be?

U.S.A. -( The Mossberg 590 Shockwave has received some mixed reviews due to the unorthodox nature of the firearm. Further clouding the perception of the 590 Shockwave, it was used to unlawfully shoot and kill a man over a discarded mattress. All of that aside, I think the Mossberg 590 Shockwave can be better than you might have originally thought.

The Mossberg 590 Shockwave is a ton of fun as a range gun, but what about using it as a serious defensive weapon or even using it to do some hunting? The Shockwave will hold its own in defensive roles in stock form and can be well suited for small spaces like an RV or houseboat, the question is how much more capable is the firearm when you add something like a Brownells Boom Kit?

The latch on the Aridus QD Side Saddle is very easy to access yet still protected from releasing the carrier unintentionally.

When I picked up my Mossberg 590 Shockwave, it was with the intention of turning it into a short barrel shotgun in the future. Until then it was the perfect candidate to install a bunch of parts on for the purpose of testing several items at once … plus it looks pretty damned cool.

Legal Mumbo Jumbo

If you aren’t familiar with the legalities of the 590 Shockwave in its stock form, it is a bit convoluted. Since the overall length is over 26″, the Shockwave doesn’t fit the definition of an AOW and it technically isn’t a shotgun because the Shockwave isn’t designed to be fired from the shoulder.

What that means is the shockwave doesn’t fall into ANY of the subcategories that define firearm types. Officially it is classified as a 12 gauge “firearm.”

Even though it looks like a short barrel shotgun, the SB Tactical brace ensures the Shockwave maintains its status as a firearm.

The very same reason that the Shockwave exists can also land you some hot water should you start throwing parts at it without understanding what that does to the classification of the firearm.

Be careful when replacing the birds head style grip on the Shockwave, it could land you in hot water.

Add a pistol grip instead of the birds head style grip that ships with the Shockwave and you have created an NFA regulated AOW because the overall length drops to under 26″. What about adding a stock? Without volunteering $200 dollars for the ATF to steal unconstitutionally, you have now created an unregistered short-barreled shotgun.

Modifying The Mossberg 590 Shockwave

I should come clean with you all … I only shot 25 rounds through the Shockwave before installing the Brownells Boom kit. It was a gun, it was fun to shoot, and it went bang. But that wasn’t why I got a Shockwave to begin with.

Like many other guns, the 590 Shockwave is a great base to start with should you want a firearm more tailored to your needs thanks to a healthy aftermarket. This exact characteristic is one of the reasons that guns like the Glock 19, SIG P320, and Remington’s 700 have sold so well.

In stock form, the Mossberg 590 Shockwave is still a capable firearm, but not as capable as I believe it can be.

Recoil in stock form is manageable but still stout seeing as it relies on two points of contact. The shape of the birds head grip does an acceptable job at staying in place during recoil but if you don’t have a solid grip there is a chance to wack your finger on the plastic trigger guard.

The factory forend on the Shockwave has a fabric loop to help you not shoot your hand off.

Everything that I installed on the gun was with the intention of seeing how effective the Shockwave could be regardless of how ludicrous the internet thought the base firearm is.

While I would love to dive into each part I installed in-depth, the review would look less like an article and be closer to a book. If there are requests for a particular review in deeper detail, there is a good chance that may happen.

Brownells Boom Kit

The Brownells Boom Kit included a 14″ Carlson’s barrel with Magnaporting and a Hi-Viz sight installed and an SB Tactical Shockwave stabilizing brace. Installing it was super easy and only required a handful of tools that most shooters have on hand already.

I found that the Magnaported barrel does an amazing job reducing recoil with any type of ammunition I shot through it. Most of the rounds fired were slugs due to the range rules at my home range, but I have spent some time putting some cheap 00 buck through the barrel. Regardless of the type of ammunition I shot, the Magnaporting performed well making the Boom Kit fitted Shockwave a joy to shoot.

When the front sight is clean, it is very easy to pick up at a glance.

There are some downsides to the Magnaporting like the carbon buildup on the front sight. While it is a small issue, it is worth noting since cleaning the steel portion that holds the fiber optic rod can be a challenge.

This wasn’t much of an issue for me personally since I have installed a red dot on the Shockwave, but I know that many of you will be running some kind of bead sight on the gun.

Annoyingly, 50 rounds cause the carbon to build up on the front sight quickly.

The only part included with the Brownells Boom Kit that I just flat out didn’t like was the SB Tactical SBL arm brace. I found it to rotate far too easily when loading the Shockwave forcing me to straighten it back out once the firearm was topped off.

I have since remedied this problem by replacing the AR-15 pistol tube and SBL arm brace with an SB Tactical SBA3 brace and carbine style buffer tube. I would love to see Brownells change the kit to include the SBA3 when they do a restock but that may increase the overall price of the Boom Kit to be less palatable.

I wish that Brownells had used an SBA3 rather than the SBL arm brace which rotates far too easy to be as useful as it could be.

The Brownells Boom Kit will add another $377.99 to the price of the Mossberg 590 Shockwave.

Surefire DSF-500/590 Weapon Light

It isn’t a secret I like flashlights on guns. Something about being able to see what is on the other end of the barrel of a gun in dim or dark conditions is reassuring. Right about the same time that I purchased the Surefire DSF-500/590 I was testing the Streamlight TL Racker on my Mossberg 590A1 and discovered that it wouldn’t fit on the Shockwave’s shorter action tube.

Since the Streamlight wouldn’t fit (they have since made a change to the TL Racker and it will now fit) the choice was easy, Surefire’s DSF-500/590 was the only option for a dedicated light.

Surefire did a pretty good job with the DSF series of forend lights. At the time this gun was put together the Streamlight TL Racker was not compatible with the shockwave.

That said, I find that I prefer the Surefire DSF light to the Streamlight TL Racker in this particular role due to the large off switch on the bottom of the light. Since the 590 Shockwave is often stuffed in a bag and goes with me on trips to the in-laws, the ability to flick a switch and prevent the light from activating in a case rather than remove the batteries is a huge benefit.

The on/off switch is a nice touch to keep the light from unintentionally being turned on when the firearm is stored.

Like the competing Streamlight TL Racker, the Surefire DSF500/590 uses two CR123A batteries. In high mode, the Surefire DSF-500/590 will provide 600-lumens for 90-minutes. Switching the light to low mode gives you 200-lumens for a whopping 180-minutes.

While the CR-123 batteries are easy to find, it is a shame that there isn’t an option that runs on 18350 or 18650 batteries.

Had I been able to use the cheaper Streamlight TL Racker for this project, I would have. But the fact that I was forced to use the tougher Surefire DSF-500/590 turned out to be a blessing in disguise and it has quickly become the light that I recommend to those looking to add a light to their pump gun when the price isn’t a concern.

Aridus Industries Side Saddle

With the rather low 5 shell capacity of the 590 Shockwave, adding a means to keep more ammo on the gun seemed like a good idea. Is the Aridus Industries side saddle overkill? Probably. I decided to get one since they had been talked about quite a lot in my circle of friends.

What makes the Aridus Industries side saddle attractive is its quick-detach ammo caddies. Unlike other designs, the Aridus won’t be affected by dirt getting into velcro.

After using it for a while, I don’t know if I would recommend it for most users. If you are someone that finds yourself reloading a lot on the range you might want to spend the extra on the Aridus side saddle, but most of you will be served well by a more traditional and cheaper side-saddle.

Adding an Aridus Industries Quick Detach Side Saddle will set you back $165 for the mounting plate and one shell carrier. If you want additional carriers, they run about $45 each.

Scalarworks Sync RMR Mount

One of the things I wanted to try with the Mossberg 590 Shockwave build was to try using a red dot sight of some kind instead of the standard bead sight or the fiber optic bead included with the Brownells Boom Kit.

The Scalarworks Sync mount uses all 4 threaded holes. The outer two are used for traditional through the mount screws, the inner two use a stud that slots into the mount to help manage the effect of the Shockwave’s stout recoil.

Since I had a spare Trijicon RMR RM02 that I had no intention of putting on a pistol due to its larger 6.5 MOA dot I started looking for a low profile RMR mount for the Mossberg 500/590 platform.

Since I had an old Trijicon RMR RM02 in the safe, adding a Scalarworks Sync mount was a no brainer.

I ended up landing on the Scalarworks Sync mount since it checked all the boxes for my needs.  I can’t tell you how pleased I have been with the Sync mount when paired with the Trijicon RMR RM02. Getting the Shockwave on target quickly is a snap and the larger 6.5 MOA dot is easy to see in all light conditions. I have not found the 3.25 MOA dot in the Trijicon RMR RM01 to be as easy to use in less than ideal lighting conditions.

The Scalarworks Sync mount will cost you $119 plus the cost of an MRDS with a Trijicon RMR footprint.

Shooting The Mossberg 590 Shockwave

Even though I don’t shoot shotgun near as much as I should, I do find myself shooting the 590 Shockwave a lot more than I anticipated. The recoil will all types of ammo, specifically the Sellier & Bellot 1-ounce Special Sport slugs that my preferred indoor range normally stocks, was mild.


My Shockwave hasn’t seen much birdshot at all since most of my range time has been on an indoor range that prohibits its use. Beyond using it for some basic skill-building or fun on the range, I can’t really find a good use for birdshot in the Shockwave.

Heck, I didn’t even pattern the gun with birdshot since I doubt I will even bother shooting more than I have in the Shockwave.


I did pattern a handful of loads with the Shockwave at the furthest defensive distances around my home which worked out to be just under 15-Yards. In order to select the best load for my application, I shot two shells at a fresh paper target 15-Yards out and measured the shot pattern.

The goal was to find a load that kept 95% of the shot inside of an average 13″ wide chest within the given range. I know you might be thinking more spread is better, but I personally dislike that idea and would prefer to deliver the maximum amount of shot to a vital area should I need to do so.

Average Spread Of Buckshot Loads at 15 Yards
Load Pellet Count Average Spread
Winchester Military 00 Buckshot 9 Pellets 11″
Armscor 00 Buckshot 9 Pellets 11.75″
Rio Royal 00 Buckshot 9 Pellets 14.25″
Winchester Ranger 00 Buckshot Low Recoil 8 Pellets 8.75″
Federal Personal Defense #4 Buckshot 34 Pellets 19.75″
Aguila Minishells Buckshot 7 #4 Buck & 4 #1 Buck Pellets 20.25″

I do have to say that the results were rather interesting, I expected the Federal Personal Defense #4 Buck to do far better rather than it did. Even though I initially had the Federal #4 Buckshot loaded in the 590 Shockwave, I quickly changed it over to the Winchester Ranger Low Recoil 00 Buckshot after seeing its impressive performance on the range.

The important take away here is that you should always test your defensive loads in your gun and not trust someone else’s data since every gun is different.


While I generally wouldn’t shoot slugs often, my preferred range requires them to prevent damage to their equipment. Had I not been forced to use them, I would have likely overlooked the most surprising aspect of the 590 Shockwave … How precise the firearm can be with standard slugs.

At 10-yards the shockwave stacked all 6 rounds right on top of another in an impressive group. I found recoil to be very manageable even though I was shooting a full power 2 3/4″ slug.

At 10-yards, the 590 Shockwave left a single hole in the target.

Even pushing the distance of the target out to 25-yards, the group that the 590 Shockwave produced was still impressive with 5 hits in the 10-ring and one line break.

The 6 shot group at 25-yards was even more impressive than the first. I imagine that the shot low of the group was likely shooter error.

While I wasn’t expecting the Mossberg 590 Shockwave to be that capable, it was a very nice surprise.

Is The Mossberg 590 Shockwave Worth Buying?

I think that the Shockwave is absolutely worth buying should you be considering one for defensive reasons. The aftermarket is strong with plenty of options out there giving you the ability to tailor the firearm to your specific needs.

In stock form, the Shockwave can best be described as “alright” but it has potential. The best advice I could give someone considering the Shockwave is to carefully consider if it fits your needs and would you benefit from modification of the firearm.

Should You Modify Yours?

This is likely going to bring some disagreement from you all, but I would highly recommend modifying the 590 Shockwave to get the most you can possibly get out of it. With so much potential, it would be foolish to ignore the possibilities.

I have to stress that you should carefully think about what you are asking of the Shockwave before throwing a lot of parts at it. You should always be able to explain why you did something to a firearm if it is to be used for anything beyond a range toy.

Adding an extended safety like this one from Brownells is almost a must on the Mossberg 500/590 series of guns.

The Mossberg 590 Shockwave will set you back $484 if you pay MSRP but prices over the last year or so have been as low as $270 at some retailers. If you were to piece together the same setup that I have shown you here it would set you back $2,243.99 should you pay MSRP. Shopping around can bring that cost down to $1250 or so look for deals and use coupon codes as you can.

Find more information about the Mossberg 590 Shockwave on Mossberg’s website.

About Patrick R.Patrick Roberts

Patrick is a firearms enthusiast that values the quest for not only the best possible gear setup but also pragmatic ways to improve his shooting skills across a wide range of disciplines. He values truthful, honest information above all else and had committed to cutting through marketing fluff to deliver the truth. You can find the rest of his work on as well as on the YouTube channel Firearm Rack or Instagram at @thepatrickroberts.

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Who in their right mind would dump between $1200-$2200 into a $300 shotgun? I love my Shockwave, but a side saddle, mini shell adapter, and a bull dot laser is all I will ever put on it. If you have over $2k to spend on a shotgun, you should be looking WAY past Mossberg and the like. This is just absurd.

Last edited 2 years ago by TyrantRex

I like the way you have it set up, but $1,250 is Fantasyland for people like me, who are crippled up, dirt poor, and in real world terms just looking for a single shot shotgun as a home defense weapon!

Single shot at this juncture is all the budget will allow! I’m sad for those folks who think a single shot is useless: 10% of something beats 100% of nothing, when the fecal matters strikes the oscillating Rotor at warp nine!

Cheers from the Oil Patch in Central WY


You mention “…I was shooting a full power 2 3/4″ (1 oz) slug.
My M590A1 (with a stock and an 18 1/2″ barrel) can chamber 3″ shells. What does it say on the side of your Shockwave’s 14 3/8″ barrel?

How about a follow-up review about the Shockwave’s controllability with that birds head grip, while running some actual full power 3″ high brass 1 1/4 oz slugs?