[Build] Ultimate Mossberg Shockwave: All The Upgrades

What’s one of the most popular new guns in the last ten years?

I’ll give you a hint: It’s mostly just a fun range toy and practically useless outside that niche.

Our mystery gun is also hard to control, deals heavy recoil, and has stoked passionate debate in the tactical community since its release.

Some love it, some hate it, and most cry, “Just upgrade it!” That’s right! Let’s open Door #1 and talk about our friend, the Mossberg 590 Shockwave (full review).

Ultimate Shockwave Build
What’s better than a Shockwave? An upgraded Shockwave!

When scouring the internet, you’ll likely come across reviews highlighting the pros and cons of the meme-worthy Shockwave.

But there is one point everyone can agree on: This model can go from greatly useless to remarkably useful with just a few clever upgrades.

My goal when constructing the Ultimate Shockwave build was to improve the original design by making it more effective as a firearm and easier to use.

I also wanted to keep the gun nice and lightweight.

How I Did It
Progress is the fruit of collaboration.

Today, I will run through my upgrade process step-by-step, from braces to grips to slings.

By the time we’re done, you should be able to build your own Ultimate Shockwave. And if you dream up a nifty Frankenwave build of your own while reading, please share it in the comments section!

Table of Contents


Is the Shockwave a Firearm or Shotgun?

The Mossberg 590 Shockwave is a unique gun model that benefits from bizarre legal loopholes.

For instance, this powerful and compact firearm is technically not a shotgun—no, not even a short-barreled shotgun!

mossberg 590 shockwave grip
Mossberg 590 Raptor Grip

Per US law, a shotgun is designed to be fired from the shoulder and must have (or previously had—you know, semantics) a stock.

Our Mossberg darling is not equipped with a stock, just a Shockwave Raptor grip.

By this technicality, the Shockwave is legally a close-quarter firearm with the giddy oomph of a shotgun, but in a smaller and more maneuverable package.

Editor's Pick Not-A-Shotgun
at KY Gun Co

Prices accurate at time of writing

Prices accurate at time of writing

As a firearm, the Shockwave is not restricted in barrel length so long as the gun’s total overall length is 26” or more. Anything less could be considered a concealable weapon, which is subject to the National Firearms Act.

And that’s the detail I kept in mind when designing the Ultimate Shockwave build.

Best Shockwave Upgrades

Stock Adapter

“Travis,” you might ask. “Surely, the best improvement is to add a stock?”

Absolutely, yes! But remember, that violates the National Firearms Act. We have to keep it legal. We’re upgrading a firearm, not a short-barreled shotgun.

So, let’s talk about the next best thing: adding a stabilizing brace.

A brace allows you to anchor the weapon to your forearm, reducing the recoil and mitigating many of the control issues associated with the original Shockwave design.

Wrathful Forces
We’re just getting started!

I also recommend using an Ergo Grip Mossberg 500/590 Tactical Stock Adapter. It bolts directly onto your Mossberg Shockwave and gives you the ability to equip an AR-15 pistol grip and an AR-15 receiver extension.

at Optics Planet

Prices accurate at time of writing

Prices accurate at time of writing

For my Ultimate Shockwave build, I added a brace and an old A2 pistol grip that was languishing in storage.

Admittedly, a pistol grip makes the safety less ergonomic, but it’s still reachable with a wide thumb grip.

Shockwave Pistol Grip
A reliable A2 pistol grip.

If you want to keep things simple, SB Tactical sells a 590-SBL Stabilizing Brace Kit complete with adapter, SBL brace, and pistol grip.

The SBL brace can’t be adjusted, but it does the job as a cheap plug and play item until you’re ready to throw more money at your Shockwave.

at Optics Planet

Prices accurate at time of writing

Prices accurate at time of writing

Brace Yourself with the SBA3 

The SB Tactical SBA3 Stabilizing Brace is one of my favorite braces for 12 gauge firearms.

Not only is it slim, sleek, and lightweight, it also allows for five different positions in which to anchor the gun against your wrist or forearm!

Pretty nifty, right?

The SBA3 is very comfortable to use and offers a QD point, making it easy to sling. It can also withstand the recoil of a 12 gauge firearm without any problems.

I know looks aren’t important when it comes to functionality, but I’m spoiled when it comes to my gear, and I find the slim design very appealing.

at Optics Planet

Prices accurate at time of writing

Prices accurate at time of writing

XS Sight Systems Big Dot Tritium Sight

Bead sights are easy to use, easy to see, and on a weapon like the Shockwave, they work reasonably well.

But you have better options.

One simple but significant upgrade to the Mossberg Shockwave is swapping out the factory bead for an XS Sight Systems Big Dot Tritium Sight.

Despite its name, this product is roughly the same size as a standard bead and is manufactured with an easy-to-see white ring surrounding a tritium vial.

This unique design functions to improve your sight acquisition speed under any light conditions, day or night.

In other words, you’ll be able to quickly and easily engage your target, even in low light settings.

Good news: The installation process is easy, and the XS package comes with all the necessary parts you’ll need to affix the upgrade to your gun.

at Optics Planet

Prices accurate at time of writing

Prices accurate at time of writing

Ditch the Factory Pump

I like the idea behind Mossberg’s pump with a strap, but I can’t say I’m a fan of the execution. The screws securing the strap to the pump dig into my hand and cause serious pain whenever I’m firing buckshot loads.

So, I quickly ditched the factory pump for an Ergo Mossberg Forend M-LOK, and I have no regrets to this day.

Ergo Mossberg Forend M-LOK
Ergo Mossberg Forend M-LOK
Check out those M-LOK slots!

It’s cool. It’s handy. What’s not to love?

The Ergo Mossberg Forend M-LOK fits properly on the Shockwave and, despite its all-metal construction, is very compact and lightweight.

Its squarish design also offers a good grip that allows you to manipulate the weapon with confidence.  

at Optics Planet

Prices accurate at time of writing

Prices accurate at time of writing

If you’re planning to use your Shockwave for home defense, you need to equip a trustworthy light.

Lucky for you (and me), this product provides plenty of M-LOK slots to mount lights, lasers, rails, and more to the weapon.

Now, about that light…

Streamlight, You Light Up My Life

There are plenty of light options, and everyone has their favorites. The beauty of the Ultimate Shockwave build is that you can attach a light directly on the M-LOK and get down to business.

For my build, I mounted a Streamlight TLR-1 HL Tactical Flashlight to my Shockwave.

The Streamlight TLR-1 HL is a full-sized tactical weapon light that’s sold in various lumen outputs.

I selected the model with 800-lumens because it’s a powerful little number that’s also compact and lightweight—the two critical elements of my upgrade design.

Plus, it has easy to access controls that work perfectly with my Shockwave setup.

at Amazon

Prices accurate at time of writing

Prices accurate at time of writing

When it comes to home defense, you need a product that’s reliable in a sticky situation.

At 800-lumens, the Streamlight TLR-1 HL is more than bright enough for inside the home, and it can take a serious beating.

If I’m identifying a target in the dark, I trust the Streamlight to keep working after suffering the abuse and recoil of a 12 gauge shot.

Can’t ask for more than that!

Lady Gaga
Sing it, sister.

All About the Grip 

You’re going to need a little background information to understand my choice of grip.

I suffer from chronic pain due to a nasty shoulder injury, so I find foregrips to be a bit uncomfortable, especially when it comes to firing pump-action weapons that require repetitive motion.

To mitigate the pain, I tend to prefer angled foregrips and vertical grips on my guns.

The IMI Defense Front Support Grip is an angled foregrip that is both supportive and comfortable to use.

When shooting 12 gauge pump-action weapons, I employ a push-pull method that requires a strong grip to reduce the recoil (and pain). The IMI Defense Front Support Grip facilitates this practice and helps me enjoy a fun day at the range.

at IMI Defense

Prices accurate at time of writing

Prices accurate at time of writing

While the IMI Defense Front Support Grip is an excellent foregrip, it’s hardly the only product on the market.

A Magpul AFG2 Angled Foregrip could easily fill this role, and BCM makes some awesome stubby grips. The new SIG Tread M-LOK Grip Kit is also a great option.  

The One Sling to Rule My Shockwave

I have a confession to make: I’m a Blue Force Gear Vickers Sling fanatic.

This disclaimer is not an exaggeration; in fact, I factor in the price of a BFG sling whenever I purchase a new gun.

I Regret Nothing
Life is too short for regrets.
Equip your Ultimate Shockwave with the sling it deserves.

But I promise these slings are worthy of my biased love and devotion. What can I say? BFG has never let me down.

When I got out of the USMC in 2013, I took my BFG Vickers Sling with me as a memento. I used this sling for a good portion of my career, which included a rough year-long deployment.

That sling is now equipped to an AR-15 and still enjoys regular use. Can there be a better endorsement?

My Precious Sling
This is you after one day of using the ONE Sling.

When I was plotting my upgrades list, I knew a BSG sling was going to make the cut. And not just any sling, but the ONE Sling, which is aptly named because for my Shockwave, it is the one sling to rule them all.

The One Sling is a 1-inch strip of webbing that’s perfect for a lightweight, versatile, and low-profile build.

This two-point sling is comfortable to wear, weighs 23% less than similar Vickers products, and is equipped with rapidly adjusting pull tabs.

We need to discuss the magical pull tabs.

You can grip or rip the pull tabs to instantly change the length of the sling. For example, it can tighten to the point where you can let go of the gun and use both hands, and then, in a flash, loosen up to a length that maximizes mobility.

What? It’s super cool. Try it and see.

at Blue Force Gear

Prices accurate at time of writing

Prices accurate at time of writing

Bonus Round: Your Shockwave Wants the OPSol Mini-Clip 2.0

The last upgrade I made to my Mossberg 590 Shockwave was equipping the OPSol Mini-Clip 2.0.

This adapter is a simple drop-in device that lets your gun feed those adorable 1.75” mini shells with reliable gusto.

It’s an optional upgrade, but certainly worthy of your time and money.

Sure, the factory Shockwave model feeds mini shells well enough without the clip, but it’s hardly dependable or consistent. And it’s incomparable to the joy you’ll experience after installing the OPSol Mini-Clip 2.0.

Want more good news? The installation process is a breeze.

The little wedge drops in easily and is tough enough to take some serious use and abuse.

It’s a simple and ingenious design that works perfectly with the Mossberg 590 series and our Ultimate Shockwave build.

at OpSol

Prices accurate at time of writing

Prices accurate at time of writing

Feel the Shockwave

Ready to start building an Ultimate Shockwave of your own? You won’t regret it!

Complete Ultimate Shockwave
My very loved Mossberg 590 Shockwave: “Ultimate” edition.

The construction of the Ultimate Shockwave build started as a mission to make the gun useful, lightweight, and simple to use.

Not to brag, but I think I’ve successfully hit all three targets. The weapon is now easier to handle, more comfortable to shoot, and boy does it pack a formidable punch.

Plus, the weapon is still over 26” in length, so there aren’t any NFA issues to worry about!

Ready to start constructing your own Ultimate Shockwave? What upgrades are you planning? Let us know below. 

And if you’re interested in exploring more ideas, check out The Best Mossberg 500 and 590 Upgrades.

It’s Alive
Your moment has come!
Tell us about your upgrade successes and failures (these are fun too!) in the comments.

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18 Leave a Reply

  • Wil Golden

    Just one man's opinion, but I think y'all are missing the point. If you want / need a big, tactical riot shotgun, then buy one. Mossberg, Remington and Winchester all have them available cheaper than this Shockwave. The Shockwave, et. al. seem to me to be a purpose built item, designed for a specific purpose, at which it EXCELLS. Short Range, GetthehellOFFAME, raw firepower, for which a "real" shotgun would be bumping into everything. 20 - 25 yard maximum, nasty firepower in a handy room clearing package. I'll add a light, and K.I.S.S. This little handful of nasty works for me.

    2 months ago
    • Aaron A. Brooks


      2 months ago
  • Davin Valkri

    An interesting upgrade path! But...would it not be simpler and cheaper to buy a standard configuration Mossberg 590? Even the upgrade 590A1 can be had for under $600, which would be less than the cost of the Shockwave, brace, and adapter.

    2 months ago
    • Travis Pike

      Yes sir! And I own a few 590s! But this was a bit of a fun project to get something short and fun

      2 months ago
    • David, PPT Editor

      If you were okay with a longer OAL, then yes the normal 590 is awesome! But by using a Shockwave you're able to get a firearm with a shorter barrel and a brace without running into NFA laws.

      2 months ago
  • Xaun Loc

    I hate the fact that these Pew Pew Tactical articles let you know how many comments have been posted, but will not let you see those comments without FIRST posting a new comment. So, OK, this is a useless comment so that I can see the other comments.

    2 months ago
    • David, PPT Editor

      Hello! Ya, we're looking into that... not sure why it is doing that all of a sudden :(

      2 months ago
  • Aaron A. Brooks

    Thanks for the article. Very informative as there is a lot of misinformation floating around about the Shockwave and its legality, especially with an added pistol brace and grip. I purchased mine, did some extensive research, and added the following upgrades/MODS, which to my knowledge, are ATF/NFA compliant. There is a ton of ambiguous information flying around the internet regarding the Shockwave, but after personally speaking with SB Tactical and Mossberg, I'm 100% certain that my MODS are NFA compliant. Now to my MODS: #1. Leapers UTG Green Bull-dot Laser Sight (This sight is a tank. Easy to hold zero at CQB ranges (5-25 yds) and holds up to extreme punishment). #2. Ergo Adapter w/Mil-Spec Buffer Tube. #3. Gisselle Buffer Spring Assembly (The SBA4 sadly does not come with a buffer spring assembly). #4. SBA4 Tactical Pistol Brace. #5. NDZ Enhanced Slide Safety (tough aluminum construction that greatly enhances my grip and ability to switch the safety on/off from the ready position. So MUCH easier to operate than the stock plastic safety). #6. Monstrum Aluminum 5 Shot Side Saddle w/Picatinny Rail (Solid as a rock, but not built for speed reloads). #7. Ergo Overmolded AR Grip (comfortable as hell, and better in hand than the Hogue and Wilson AR grips I had lying around). Overall, this "firearm" is awesome! It's devastatingly powerful in a home defense situation or at CQB range, and will most certainly incapacitate/devastate/destroy anything within 25 yards at center mass with 00 buckshot or slugs. The spread is minimal with tight groupings, which is comforting as I live in an apartment with thin walls). On my first trip to the range after adding my MODS, everyone stopped to ask me what I was shooting, as my Shockwave was obliterating the targets at 10-25 yards (and that was with target loads of small buckshot). Once I loaded the 00 Buck and rifled slugs, game over, and less recoil oddly enough? I've shot Benelli's most of my life, but LOVE this firearm. It's simply well made, elegant, mean as f%$#@, and unapologetically effective. More importantly, at CQB range, it's extremely accurate and equally devastating. With the addition of the pistol brace, it's as effective as a standard 590, without the added weight and longer barrel length (I personally prefer the shorter barrel for maneuverability). The only downside is the recoil. Even with the MODS, my "shoulder" was black and blue from putting 100 rounds downrange. Hopefully, I can improve my stance and mitigate recoil. Future MODS are a Blackhawk Knox Breachers Grip (to mitigate recoil per Pew Pew's excellent review), and tactical light (Highly recommend the O-Light). Thanks for listening. Pew Pew, or Boo-Ya rather!

    2 months ago
  • TomC

    The problem with this "upgrade" from the birdshead grip to the wrist-breaker pistol grip and the so-called brace is that it too violates the NFA. Not by being a stock, but by being an unnecessary accessory. Because it is an accessory that is not an essential part of the firearm, it doesn't count towards the overall length of the gun. The ATF has already ruled that braces no not count towards OAL on ARs because they are an accessory -- the buffer tube does count because it is an essential functional part of the AR, but the brace does not count towards OAL. There is no way that the same logic would not apply here. If the brace doesn't count towards the OAL, your "upgraded" shockwave is no longer a non-NFA firearm, the instant it fell below the magic 26" overall length it became an AOW -- and in this case, an unregistered AOW. But, of course, you guys are the experts and I'm just a poor country bumpkin who spent his career as an Administrative Officer with the federal government responsible for interpreting, implementing, and writing regulations, so obviously you know more about this than I do. Since you KNOW that your "upgraded" shockwave is legal, feel free to drop by your local ATF office where they can confirm that for you.

    2 months ago
    • Travis Pike

      Remington literally sells a braced version of the Remington Tac 14. A company called Black Aces Tactical has been selling braced 12 gauge firearms longer than all of them. G&GG and SB Tactical sell kits made specifically for firearms. There are dozens of small vendors that sell braced 12 gauge firearms and display them all over SHOT. Do you know who is at shot? The ATF. In fact, all the ATF has said about braces on firearms is that they measured in their shortest configuration. You are spreading misinformation and should do more research.

      2 months ago
    • Aaron A. Brooks

      If you add an SBA4 or SBA3 Pistol Brace with the Ergo adapter to the Shockwave, the OAL is more than 26" (on my Shockwave, it's 28"). That is if you are accurately measuring from the tip of the muzzle to the end of the buffer tube, which is not an "accessory" per the ATF. Definitely not trying to discount your wisdom, experience, or knowledge, just making a point from my understanding of the NFA rules. Please correct me if I'm mistaken, as the rules are very "grey".

      2 months ago
  • Mark West

    A Crimson Trace laser for the 590 made "aiming" painless. It's not bulky and activates easily with the stock bird's head grip.

    2 months ago
  • Travis Pike

    Let me know if you guys have any questions

    2 months ago
  • Bob

    This reminds me of the old bathtub racers that would try to one-up their competition every year until they all had what were essentially Formulae 1 cars with bathtubs strapped on top...(this does look like a good 590 mod though..).

    2 months ago
  • Chris

    I put a light and a red dot, Easier to aim, will welcome anyone that wants to try to get in!

    2 months ago
  • mkb

    Will any of this work on the 20 ga model? Thanks!

    2 months ago
  • Fred

    Is the Shockwave receiver tapped for a 590 rail? I would want to add an optic.

    2 months ago
    • Aaron A. Brooks

      Yes. You can add a Pic rail. I highly recommend the Monstrum Side Saddle and Pic rail. Takes 5 min to install and will easily accommodate most Pic Rail mountable optics. Easy peasy.

      2 months ago
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