O.F. Mossberg and Sons is the oldest family-owned firearms manufacturer in the United States opening their doors in March of 1919. I’ll admit up front that I’m a Mossberg fan because of their products, customer service and innovation.

That innovation includes compact and subcompact pistols, and they’ve done it once more with shotguns that will reliably chamber 1 ¾”, 2 ¾” and 3” shotshells. Yes, I have seen some shotguns that will cycle the mini-shells, but it’s a hit and miss proposition and when it comes to self-defense reliability is paramount.

Known as the 590S, the 12-gauge shotguns are available as Shockwave versions (14-inch and 18.5-inch barrels) and full-size 590’s with 18.5 and 20-inch barrels.

I received the 20-inch version from Mossberg for this evaluation.


Like all Mossberg’s in the 500/590 series, the shotgun features dual extractors, positive steel-to-steel lockup, twin action bars, and an anti-jam elevator ensure smooth operation.

The 590S incorporates three new components and include a redesigned elevator and bolt slide and the addition of an energy absorbing bumper to allow cycling the full range of shells—interchangeably.

The top mounted safety provides for ambidextrous operation. Also, the action release can be operated with either hand without releasing the firing grip.


Mossberg 590S is available in four variations. Author evaluated full-size version with 20-inch barrel.


Mossberg 590S is more versatile than ever by being able to cycle 1 ¾”, 2 ¾” and 3” shotshells.



The forend has 15 full-size M-LOK slots and six smaller slots that offer a multitude of mounting options for attaching lights or lasers.

A fully adjustable ghost ring rear sight is complemented by a ramp front sight with an orange insert. The magazine tube mounts a bayonet lug and the magazine cap is easily removed to clean out the magazine tube.

The muzzle of the 20-inch barrel is threaded for a screw-in chokes. A cylinder bore Accu-Choke is included along with a choke wrench.

My biggest complaint with most manufacturers over the years, Mossberg included, is the length of pull of the factory stock. The 13.87-inch LOP is almost too long for most folks. Good technique can be maintained with a shorter stock much easier than one that is too long.

My personal 590A1 has been equipped with an adjustable Magpul SGA/MOE stock. I take out all the spacers for a 12.25-inch LOP making it very usable from light clothing to heavy winter coats.

Capacity with different length shells is as follows:

• 13+1 with 1 ¾” shells

• 8+1 with 2 ¾” shells

• 7+1 with 3” shells


I first fired the 590S at a new product rollout event at Gunsite. Attendees extensively fired the 590S with all three shell lengths, mixing and matching them, through all four versions of the shotgun.

The only problems I observed were with the fairly recently released 1 ¾-inch shells from Federal. While they extracted fine, they would not always chamber reliably. There were no problems with the Federal 2 ¾-inch or 3-inch shells.

Aguila Ammunition has been producing mini-shells for decades and seems to have the recipe down pat. There were zero malfunctions of any kind while using the Aguila ammo while mixing it with 2 ¾ and 3-inch shells.

When I received my review sample I fired around 100 rounds of the 1 ¾-inch shells and slightly more 2 ¾-inch shells. I only fired 20 rounds of the 3-inch type.


Safety is positioned for ambidextrous use. Rear ghost ring sight is fully adjustable.


Forend has 15 full-size M-LOK slots and six smaller slots.



Front side is a blade on a ramp. Blade has orange insert.



First let’s look at the basics of each round. As this is not a shotgun to take dove hunting, we’ll confine the discussion to buckshot.

The Aguila buckshot loads consist of seven #4 buckshot pellets and four #1 buck. To put this in some perspective #4 buck is .24 caliber and #1 buck is .30 caliber. Felt recoil is very mild.

The number of 00 buckshot in a 2 ¾-inch round varies from eight pellets in a premium load to 12 pellets. Generally speaking the eight or nine pellet loads produce tighter patterns at longer distances. This is more important to peace officers on the street with possible bystanders than the private citizen defending his home against an intruder. A 00 buckshot pellet is .33 caliber. As expected, felt recoil with the heavier load is more significant, but very manageable especially when using good technique.

A premium 3-inch 00 buckshot shell contains nine pellets. That’s only one more pellet than a 2 ¾-inch shell, but fired at a higher velocity. Recoil is usually quite substantial. Personally I never felt the wear and tear on my shoulder from a 3-inch shell was worth whatever I might gain downrange.

It’s obvious that each length of shell has advantages and disadvantages. It’s up to the user to decide what gives them the most bang for their buck.

With the twenty-inch 590S, using the mini-shells gives a significant capacity increase of just over 64 percent compared to 2 ¾” shells. The 1 ¾-inch rounds might be a slightly better choice as well if you’re concerned about over-penetration. I say “slightly better” because contrary to popular myth even birdshot will penetrate a sheetrock wall unless a stud is hit.



Like the 590A1, the magazine tube features a quick magazine cleanout and bayonet lug.


590S incorporates three new components including a redesigned elevator and bolt slide.


On the other hand, if a lower capacity does not bother you, the 2 ¾” 00 buck is a better fight stopper. As for overpenetration, it might actually be desired in the event a crazed thug is trying to kick in the solid core door of your bedroom.

One of the best things about being an American is the ability to make choices. And the American-made Mossberg 590S does just that. One of the strongest attributes of the shotgun is that it can perform multipurpose roles, and the 590S is now more versatile than ever before.