Mossberg 590S Magpul 12Ga 18.5" 9-Round Gray Optics-Ready Shotgun

The Mossberg 590S Magpul 12Ga 18.5" 9-Round Gray Optics-Ready Shotgun is a modern pump-action built for shooters who want real versatility without compromise. Unlike traditional 12-gauge shotguns locked into one shell length, the 590S cycles 1.75-inch, 2.75-inch, and 3-inch shells interchangeably—load them individually, mix them in the same magazine, or switch loads on the fly depending on your task. That flexibility eliminates the need for shell adapters and lets you tune your ammo to the job: light recoil practice loads, standard hunting rounds, or magnum loads, all from the same gun.

The platform is built on proven Mossberg pump-action DNA: dual extractors, twin action bars, positive steel-to-steel lockup, and an anti-jam elevator keep things running smoothly under hard use. The 590S engineering includes a redesigned elevator bolt slide and energy-absorbing bumper for durability. The optics-ready top rail is pre-mounted with a Holosun HS407K micro dot, so you're set up for fast target acquisition right out of the box. The 18.5-inch barrel with Cylinder Bore Accu-Choke and bead sight gives you a nimble, controllable platform suited to home defense, close-quarters hunting, or tactical training.

Ergonomics matter on a shotgun you'll actually use. The Magpul SGA adjustable stock (with spacers) lets you dial in length of pull from 12.25 to 14.25 inches—critical for comfort and control with body armor, heavy clothing, or different shooting positions. The Magpul MOE forend gives you a positive grip even when wet or gloved. Ambidextrous safety means left and right-handed shooters operate the gun without fumbling. The gray Magpul furniture is tough, lightweight, and designed to work hard. A 9+1 capacity (9 rounds in the tube, 1 in the chamber when loaded with longer shells) keeps you in the fight, while the magazine clean-out tube makes maintenance straightforward.

If you're looking for a 12-gauge pump that adapts to your needs instead of forcing you into one role, the 590S Magpul delivers the gear and the capability to back it up.

Key Features

• Cycles 1.75", 2.75", and 3" shells interchangeably—no adapters required
• Pre-mounted Holosun HS407K micro dot for immediate optics-ready setup
• Magpul SGA adjustable stock with spacers (12.25–14.25" LOP) for proper fit and control
• Magpul MOE forend for a secure, all-weather grip
• Ambidextrous safety accessible to left and right-handed shooters
• Dual extractors and twin action bars for reliable, smooth operation
• Steel-to-steel lockup and anti-jam elevator for durability
• 18.5" barrel with Cylinder Bore Accu-Choke for compact handling
• 9+1 magazine capacity (with 3" shells)
• Matte blue barrel finish resists corrosion

Specifications

Frequently Asked Questions

Can I load different shell lengths in the 590S at the same time?

Yes. The 590S is specifically designed to cycle and load 1.75", 2.75", and 3" shells interchangeably in any combination. You can load them all together in the magazine or swap between types depending on your immediate needs—no special adapters or modifications required.

What comes mounted on the optics rail?

A Holosun HS407K micro dot sight is pre-mounted and ready to use out of the box. The rail is optics-ready, so you can swap the dot for other optics if desired, or add accessories to the rail.

Is the stock adjustable, and will it fit different body types?

Yes. The Magpul SGA adjustable stock includes spacers and offers a length of pull range from 12.25" to 14.25", allowing you to dial in a proper fit whether you're smaller-framed, wearing body armor, or prefer a longer reach-back.

What's the magazine capacity of this shotgun?

Capacity depends on the shell length loaded: 9+1 with 3" shells, 6+1 with 2.75" shells, and 5+1 with 1.75" shells. When loaded with a mixed combination, capacity will vary based on the shells in the tube.