We recently tested three shorty-type shotshell-chambered firearms, one of which was a new Mossberg model, with a diverse group of mini shotgun shells to see if any of the three could handle the 1¾-inch shotshells reliably. In particular, the Mossberg 590S Shockwave firearm is purportedly designed for factory reliability with mini shells. If the gun were to work as advertised, the 590S would go a long way toward legitimizing the mini shell and its niche popularity.

However, after shooting two Mossberg 590 pump firearms and a Remington TAC-14 pumpgun, we have to point out our disinclination toward these units when compared to a standard shotgun, such as a Black Aces Tactical Pro Series S Max, tested separately. Aside from their reliability issues with the mini shells we focused on this issue, the Shockwave-type guns are also very difficult to use well, which we detail in more depth below.

Also, we remind you that these Shockwave-type firearms aren’t shotguns by definition, because they have 14-inch barrels and are just over 26 inches in overall length, which means they aren’t short-barrel shotguns and regulated as such under the National Firearms Act. The Shockwaves and TAC-14s aren’t legal everywhere, including a couple of usually gun-friendly jurisdictions. Never add a shoulder stock or pistol grip stock to the Shockwave types because this is illegal. Such modifications convert a Shockwave from a shotshell-chambered firearm to a short-barrel shotgun. Just be careful.

Mini Shell Testing

We previously tested mini shells in the August 2020 issue. Interest in these shells and the introduction of the 590S spurred this follow-up test. Unfortunately, we were unable to obtain the excellent Nobel Sport Italia (NSI) MiniBuck 6P, a 12-gauge 2.25-inch 7⁄8-ounce shotshell with six 00 buckshot pellets rated for 1250 fps. As far as we can learn, they are out of production. This is a shame because these were the best in previous testing. Instead, this round we were able to test mini shells from Aguila, Federal, Firequest, and Mason Munitions. We fired the rounds in the 14-inch-barrel Shockwaves and the TAC-14, as well as 18.5-inch barrels in the Black Aces Tactical Pro Series S Max semi-auto, a Remington 870 full-size pumpgun, and a full-size Mossberg Maverick pump.

The well-known Aguila Minishell, a 12-gauge 1¾-inch shotshell with a 5⁄8-ounce payload of 11 buckshot pellets (seven No. 4s and four No. 1s) is rated for 1200 fps, and it fired reasonably tight patterns from 18.5-inch-barrel shotguns but blossomed to 13-by-9-inch spreads out of the Shockwaves. The load delivered around 600 foot-pounds of energy on average with its dual load of No. 4 buckshot and No. 1 buckshot. The Aguila is more expensive than the Federal load at $24.38 average for 20 shells. The reason the Aguila shell made such a wide pattern was that the heavier No. 1 buckshot went high over the No. 4 buckshot pattern. While we like the cohesive Federal pattern and higher energy, the Aguila never gave the initial problems with feeding the Federal did. The Aguila shell measured 1.5 inches unfired and 1.9 inches fired.

The Federal Shorty Shotshell is a 12-gauge 1¾-inch cartridge with 15 No. 4 buckshot pellets rated for 1200 fps. It was the most affordable at $11 per 10 shells. We saw the product on-line for $9 at one outlet. We were concerned with reliability after a false start with them in the 590S. The buckshot in this load averaged a 10-by-8-inch pattern at 10 yards and delivered more than 800 foot-pounds of energy. The Federal Shorty shell measured 1.4 inches in length unfired and 1¾ inches fired.

Next, there are six balls in the Firequest Shorty 00 Buck shotshell (Firequest.com), with three over the powder wad, then another wad, and then three balls below a wad beneath the crimp. There’s also a similar load with the six 00 balls situated together under the top and bottom wads (G25-059) and a third (G25-061) that has 12 No. 4 buckshot with two layers of six shot. The Firequest load provided impressive performance. Velocity is 1115 fps, and the load averaged less than 900 foot-pounds of muzzle energy. The pattern is a tight 3.5-by-5.5 inches. By any standard, the extra penetration of 00 buck and the tight pattern make the Firequest load a desirable option. However, the load is pricey, listing at $60 per 25. That is about $50 more than 20 Federal shells. Recoil and muzzle flash are limited. The load also performed well in standard 18.5-inch barrels. Feed reliability in a Remington 870 was a failure; we could not get the first one to chamber, much less feed. The Firequest shell started at an unfired length of 1.65 inches and wound up at a 1.8-inch fired overall length.

The Mason Munitions (MasonMunitions.com) load is affordable at $25 for 20 shells. Mason also offers a well-designed mini-shell adapter ($15) that’s similar to the better-known OpSol clip. This load uses eight No. 1 buckshot (30-caliber) shells, burns clean, and feeds as well as any other mini shell. The Mason starts out at an unfired length of 1.45 inches and finishes at a fired length of 1.5 inches.

The mini-shell adapter installation is pretty easy. Make sure gun is on Safe. Ensure the firearm is unloaded, with no shells in either the magazine tube or chamber. Slide the pump slide into its extended position. Squeeze and insert the back, flat end of the mini-shell adapter into the magazine loading port at an angle.

Push the rest of the adapter down into the magazine well so that it is flush to the rear and the bottom. Slowly rack the slide a few times to make sure that the mini-shell adapter is in the correct position. It should not move. If it does, remove the adapter and repeat steps one through three.

Here’s how the various shells fed and fired in these shotshell-chambered firearms.

Gun Tests Grade: A (Our Pick)

$300

We first tested the S Max in the March 2021 issue, where it earned an A grade and a Best Buy recommendation. A big store like Palmetto State Armory offers these shotguns for around $300, which is quite a bargain. We tested it this time because it offered a standard fixed buttstock and a birdshead-style grip stock and because its semi-auto function allowed us to see how the mini shells would work. We had already done full-size-shotgun function tests with an unaltered Mossberg Maverick and a Remington 870 and found them unable to handle the mini shells reliably. In the case of the Maverick, however, it can accept a mini-shell clip from OpSol or Mason Munitions, which makes the Maverick able to feed the shorter shells.

Which brings us to the S Max. This is a viable self-loading shotgun with good features. In all firing drills with the Raptor grip in place, the Black Aces S Max completely outclassed all of the 14-inch-barrel shotguns by such a wide margin the results were almost laughable. However, the S Max will not feed or function with mini shells. But then none of the three pumps were 100% reliable with mini shells either. For reasons we will outline later, we did not find this to be a major drawback. The S Max is comfortable to fire reliably with full-power shells and offers good fit and finish. While it may seem unfair to compare this shotgun to the shorter Shockwave, it really isn’t that much larger or longer. And it works. The only drawback is that the Black Aces shotgun, when fitted with a raptor grip, is 4.7 inches longer overall than the Shockwave. We can live with that.

Elsewhere, the S Max’s finish is superior to either the Shockwaves or the TAC-14. The blued finish is dark, deep, and well done. The walnut stocks are nicely finished. The shotgun is supplied with a birdshead grip to allow the shotgun to be used at close quarters and stored easily. With the birdshead grip attached, the shotgun remains a legal length because the barrel is 18.5 inches long. The shotgun is supplied with three choke tubes, giving the S Max much versatility. While changing the stock requires some time and elbow grease, you may hunt with shotgun — it makes a crackerjack bird and rabbit gun — and store it ready for home defense with the raptor grip if you so chose.

To operate the Black Aces shotgun, rack the bolt before loading then press the decocker button. The Black Aces Tactical features an extended bolt lever to make racking the bolt easier. Then you begin loading the magazine. The Black Aces Tactical shotgun magazine holds six shells, one more than other shotshell arms tested. If you attempt to rack a shell into the magazine without pressing the decocking lever, the shotgun will not load. In other words, the bolt must be released before the chamber is loaded — but the bolt is racked before the shell carrier is pressed upward to load the shotgun.

The Black Aces Tactical shotgun has a total capacity of seven shells, with a shell in the chamber and six in the magazine. This beats the Mossberg’s standard capacity handily and is within two shells even if the Mossberg is loaded with mini shells. The recommended home ready condition, with the chamber empty, allows six shells to be ready.

The safety is a crossbolt type and is positive in operation. This shotgun is more similar to the Benelli M2 types than the later M4, but the Benelli influence is present in this shotgun. The S Max uses a simple front post for aiming. It is easily picked up for fast shooting. The controls are easily manipulated. The trigger is nice at 6.0 pounds even.

The Black Aces shotgun was fired in equal amounts with both the standard stock and birdshead grip. The shotgun was surprisingly easily to control with the birdshead grip. The Black Aces Tactical S Max weighs 6.5 pounds. By holding the birdshead grip and pushing forward while pushing to the rear with the fore end, the shotgun was controllable, and we had good results with the birdshead grip to 7 yards. With the standard stock installed, the shotgun was easy to use well. The Black Aces S Max shotgun never failed to feed, chamber, fire, or eject 2¾-inch shells. With the standard stock installed, we fired slugs with good results, a 3-inch group at 15 yards. The Shockwave isn’t viable at long range with any load.

The Black Aces is a simple shotgun well fitted to personal defense and home defense. The shotgun simply blazed away without fault, completely outclassing both short shotshell firearms when using buckshot and birdshot loads. Sure, it is 4.5 inches longer or so in the barrel, but what a difference this makes. The other firearms are worthless for slug firing. The Black Aces S Max will deliver slugs on a human silhouette target out to 50 yards.

Our Team Said: While some may say we are comparing apples to oranges, we are actually outlining choices for home defense. None of our test team can imagine choosing a Shockwave firearm over a shotgun similar to the Black Aces S Max. We tried- and the Black Aces will not function with mini shells. No surprises at all there. We also obtained a second used version with black stock just to confirm our good impression of the S Max. The second shotgun, found without a box or raptor grip, came with a few dings. It worked as well as the original.

For us, we’d choose the S Max over the 590S Shockwave as a defensive shotgun for home, auto, plane, or boat and stoke it with 2¾-inch shells.

The Bottom Line

After you read the sidebar reviewing the Black Aces Tactical Pro Series S Max, come back over here and read our conclusions on choosing a Shockwave-style firearm versus a short semi-auto or pump for home defense.

The logic of choosing a mini shell with about 50% of the energy of a standard buckshot load doesn’t make much sense to us. Better to learn to control recoil or use reduced-recoil buckshot loads that remain effective. Also, save in a single from-the-factory shotgun, the 590S, mini shells are unreliable in every short gun we’ve tested. Moreover, our team noticed some other issues:

Sacrificing a three-point hold on the shotshell firearms leads to misses. A slight movement of either hand on a Shockwave-style firearm results in an errant shot, which can create lifelong trouble.

There is no viable means of firing a Shockwave from cover.

Another serious concern is retention, which includes using leverage to free the shotgun from an attacker’s grasp and butt-stroke the adversary. This isn’t as feasible with the Shockwave.

Rapid reloads are problematic. It is difficult enough to practice quickly reloading the shotgun’s tubular magazine with the weak-side hand. During high-stress events, shooters often drop 2¾-inch shells. This results in many using the violin-type reloading drill, which uses the strong-side hand to reload the shotgun riding on the shoulder. Mini shells are extremely difficult to handle quickly using a standard or violin reload technique.

A folding stock or pistol grip shotgun isn’t as desirable as a fully stocked shotgun, but they remain well ahead of the Shockwave-type firearm. Yes, you could buy a 590 Shockwave and add an OpSol Mini Clip or Mason mini-shell adapter, but why? A regular shotgun with either a standard stock or a pistol grip stock, or both, as with the Black Aces shotgun, seems to be a better choice for most people.

Just the same, if your mind is made up and you must have one of the shotshell firearms, the Mossberg 590S Shockwave is an answer to many problems. As a boat gun for dispatching sharks at close quarters, or in a carefully considered home-defense situation for use at a few feet, or in an auto, where legal, the Shockwave has one overwhelming advantage over a pistol, and that is power.

If you own Mossberg 500 or 590 or the Maverick 88 shotguns and you want to fire mini shells for fun and practice, order the Mason Mini Shell Adapter or the OpSol clip. We find they work at least as well as the 590S, are affordable, and are easy retrofits. Just be certain your shells feed from all the firing positions you might encounter.

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