Mossberg 590S

What Are Mini Shells and Why Does the 590S Matter?

Aguila Minishells are 1¾″ 12-gauge shells—shorter than standard 2¾″ loads—that load more rounds into a fixed-length magazine tube. A standard Mossberg 590 holds 8+1 with 2¾″ shells; the 590S with a 20″ barrel holds 13+1 with Aguila Minishells. The challenge has always been reliability: most pump shotguns don’t cycle mini shells reliably because the shorter shell doesn’t engage the shell stop correctly. The 590S solves this with a redesigned elevator, shell stop, and carrier geometry that accommodates all three shell lengths—1¾″, 2¾″, and 3″—reliably from the same magazine. This makes the 590S unique: it’s the only production pump shotgun that cycles all three lengths without any modification or adapter.

590S vs. Standard Mossberg 590: Should You Upgrade?

The standard Mossberg 590 is one of the most proven tactical pump shotguns ever built, with a military track record going back decades. The 590S adds the mini shell compatibility while maintaining full reliability with standard loads—it’s a strict superset of the 590’s capability. If you run only standard 2¾″ or 3″ shells, the 590 and 590S perform identically. The 590S’s value is specifically for users who want the capacity advantage of mini shells or the option to use reduced-recoil mini shell buckshot for home defense. For a buyer choosing between the two today, the 590S’s additional capability at a modest premium makes it the more versatile choice.

Mini Shell Performance: Is the Tradeoff Worth It?

Aguila Minishell buckshot loads (typically #4 or #1 buck) produce less recoil and less pattern density than full-size buckshot loads. For home defense at typical indoor distances (under 15 yards), the reduced payload is still effective—a 1¾″ shell’s buckshot charge covers the target adequately. The recoil reduction is meaningful for shooters who are recoil-sensitive or training family members on the shotgun. The capacity advantage (13+1 vs. 8+1) is the primary tactical argument for mini shells. Federal Shorty Shotshells also offer slug and birdshot configurations in the mini-shell format. For maximum defensive effectiveness at any range, full-size 00 buckshot remains the gold standard; mini shells are the choice when capacity is the top priority.

590S Configurations: 18.5″ and 20″ Barrel Options

Mossberg produces the 590S in 18.5″ (9+1 with standard shells, up to 10+1 with mini shells) and 20″ (8+1 standard, 13+1 mini shells) barrel configurations. The 18.5″ is more maneuverable in close quarters; the 20″ maximizes mini-shell capacity and provides a slightly longer sight radius. Both use Mossberg’s tang-mounted safety, ghost ring rear sight with bead front on some configurations, and the proven 590 action. The 20″ configuration is the more popular choice for home defense given the capacity advantage with mini shells. Both accept standard Mossberg 590-compatible accessories and aftermarket stocks.

590S as a Home Defense Shotgun: An Honest Assessment

The 590S in 13+1 configuration with Aguila Minishells is a genuinely compelling home defense shotgun. Thirteen rounds of buckshot before reloading covers virtually any realistic defensive scenario with margin to spare. The tang safety is fast and intuitive. Ghost ring sights provide a more precise sight picture than a plain bead. The pump action’s mechanical simplicity means it will cycle whatever you feed it without worrying about cycling reliability from a cold, dirty, or long-stored condition. The 590S’s only real limitation is that running mini shells for practice is more expensive than standard promotional buckshot—standardizing your practice ammo on 2¾″ loads and keeping mini shells for the defensive load is the practical approach.

Frequently Asked Questions: Mossberg 590S

What makes the Mossberg 590S different?
The Mossberg 590S is a specialized variant of the 590 series designed specifically to cycle 1.75-inch Aguila Mini Shells — a shortened 12 gauge shotshell that dramatically increases magazine capacity. Where a standard 590 holds 8+1 rounds of full-size 2.75-inch shells, the 590S in the same platform holds 13+1 rounds of Aguila Mini Shells. This capacity increase makes the 590S one of the highest-capacity pump-action shotguns available without magazine extensions. The 590S cycles both Mini Shells and standard 2.75-inch shells reliably through its OptiMag system — standard 590s and 500s require an aftermarket OPSol adapter to feed Mini Shells reliably.

Are Aguila Mini Shells effective for home defense?
Yes with appropriate selection. Aguila produces Mini Shell loads in 00 buckshot (7 pellets of #1 buck per shell), birdshot, and slug configurations. The 00 buckshot Mini Shell delivers less total payload than a standard 00 buck load — 7 pellets of #1 buck vs 8–9 pellets of .33-inch 00 buck — but at close defensive distances the difference in terminal effect is minimal while the capacity advantage is significant. For home defense users who prioritize capacity, the 590S with 00 Mini Shells is a legitimate configuration.

Can the 590S fire standard 2.75-inch and 3-inch shells?
Yes — the 590S is chambered for 3-inch shells and cycles 2.75-inch and 3-inch standard shells reliably. The OptiMag system allows reliable cycling of both Mini Shells and standard shells without user adjustment. The 3-inch chamber does not accept 3.5-inch shells.

How does the 590S compare to the standard 590A1?
The 590A1 is the military-specification heavy-duty variant with a heavier barrel and metal trigger guard — the most durable production pump-action available. The 590S uses the standard 590 platform without the A1’s mil-spec upgrades, trading the A1’s durability premium for the OptiMag mini-shell capability. For pure home defense where capacity matters most, the 590S; for maximum durability and sustained use, the 590A1.

See Also: Mossberg 590A1 • Mossberg 500 • Tactical Shotguns • Pump Shotguns • Home Defense