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: C-

$423

This was our first test of the TAC-14 12 gauge. A 20-gauge 81145 version was reviewed in the March 2019 issue and got an A- grade. It was not fired with 20-gauge shorty shells because they weren’t available.

It is unusual to see this Remington priced lower than the original Mossberg, but this was true in our South Carolina test area at the time of our test. The TAC-14 is similar to the Shockwave in set up. There is no support strap on the fore end, but we had no difficulty in controlling the Remington. There is a stop or ridge on the end of the fore end that seems effective in preventing the hand from running forward. Just the same, the Mossberg strap is seen as a fail safe to prevent the hand from slipping close to the muzzle on firing.

The Remington’s M-Lok fore end allows mounting a combat light or laser, which the tested Mossbergs lack. The Remington features a crossbolt safety. We found it engaged in a positive manner. Most raters say the Mossberg safety is easier to use quickly. A fly in the ointment was a very stiff safety on one of the Mossberg shotguns.

The Remington’s action is markedly smoother than either Mossberg, we felt. The much smoother dual-bar action is an advantage of the Remington. The Mossbergs also have dual arms, but they were much more difficult to operate quickly. One rater noted that his Mossberg 500 Retro shotgun is smoother than either of the 590 shotguns.

The Remington holds one fewer round than the Mossbergs. With 2¾-inch shells, four shells should be adequate for most situations. While seven mini shells may be loaded, they will not feed. Some refused to chamber. The extractor held the shell’s rim, but the nose of the shell was off and would not enter the chamber. We suffered double feeds as well.

There is no adaptor to make the Remington run with mini shells, so this isn’t a viable platform for these shells. With standard loads, the Remington was much the same in firing drills as the Mossberg. It fired high and demanded effort to get a hit.

Our Team Said: We liked the smooth action of the Remington TAC-14. But when it comes to magazine capacity and feed reliability with mini shells, the 590S is the only game in town. If you plan to buy the TAC-14, plan to use it only with standard-length shells. Based on its failure to feed with mini shells and no mini-shell adapter option, as well as difficult accuracy with 2¾-inch shells, we’re hard-pressed to recommend this item for home defense. If you are going to use standard-length buckshot, there is little real difference between the Remington and Mossberg products.

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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