Description

The Mossberg 590 Mariner 12 Gauge 20in Pump Shotgun is built to handle salt spray, rain, and rough use without rusting or jamming. Its Marinecote finish on the barrel and metal parts gives you a tough, corrosion-resistant shotgun that keeps working when you need it most. With a 20-inch barrel, synthetic stock, and a pistol grip conversion kit included, this pump-action 12 gauge is ready for home defense, boat duty, or range practice.

Manufacturer	Mossberg
Model	590 Mariner
Material	Synthetic stock, Marinecote-finished metal
Compatibility	12 Gauge 2-3/4 and 3-inch shells
Finish	Marinecote (silver-gray corrosion-resistant coating)
Weight	Approximately 7.25 lbs (per manufacturer specs)
Condition	New

Key Features

Marinecote Finish — WHY IT MATTERS: This silver-gray coating resists rust from saltwater, sweat, and humidity, so your shotgun stays reliable even after days on the water or in a damp gun safe.
20-Inch Barrel with Front Bead Sight — WHY IT MATTERS: The shorter barrel keeps the gun easy to swing in tight spaces, while the bead sight gives you a fast, clear aiming point for quick target acquisition.
Ambidextrous Top-Tang Safety — WHY IT MATTERS: Left- and right-handed shooters can reach and operate the safety without changing their grip, making it a great choice for families with different-handed shooters.
Pistol Grip Conversion Kit Included — WHY IT MATTERS: You get both a standard field stock and a pistol grip in the box, so you can set up the gun for your preferred shooting style or swap it for different uses.
Recoil Pad — WHY IT MATTERS: The factory-installed pad reduces felt recoil, which helps new shooters stay comfortable and focused during longer practice sessions.

Who It’s For

This shotgun is for families who want a dependable defensive gun that can handle wet or salty conditions without extra maintenance. It’s also a smart pick for new shooters because the pump action is simple to learn and the included recoil pad makes shooting more pleasant. Youth shooters and beginners will appreciate the ambidextrous safety and the option to run the pistol grip for a more secure hold.

Pros and Cons

Pro: Corrosion-resistant Marinecote finish means less time cleaning and more time shooting.
Pro: Versatile with two stock options in the box — field stock and pistol grip.
Pro: Proven Mossberg reliability with a strong aftermarket for parts and accessories.
Con: The synthetic stock may feel slightly flexy under heavy recoil compared to wood or aluminum stocks.

Comparison vs Competitors

Feature	Mossberg 590 Mariner	Remington 870 Express	Benelli Nova Tactical
Finish	Marinecote (corrosion-resistant)	Parkerized (good, but less salt-resistant)	Black synthetic with nickel-plated bore
Barrel Length	20 inches	18.5 or 20 inches	18.5 inches
Stock Options	Field stock + pistol grip kit included	Field stock only	Fixed synthetic stock
Weight	~7.25 lbs	~7.0 lbs	~7.2 lbs
Capacity	6+1 rounds	4+1 or 6+1 (varies)	4+1
Price	~$720	~$450–$550	~$500–$600

Frequently Asked Questions

Is the Mossberg 590 Mariner good for saltwater use?

Yes. The Marinecote finish on the barrel and metal parts is specifically designed to resist corrosion from saltwater, making it a popular choice for boaters and coastal homeowners. Just rinse it with fresh water after exposure to salt spray.

Can I use 3-inch magnum shells in this shotgun?

Yes, the Mossberg 590 Mariner is chambered for 12 Gauge shells from 2-3/4 up to 3 inches. You can shoot light target loads or heavy defense loads without any issues.

Does the pistol grip conversion kit come with the gun?

Yes, it is included in the box. You get the standard synthetic field stock already installed, plus a separate pistol grip and the necessary hardware to swap it out.

How many rounds does the magazine hold?

The Mossberg 590 Mariner with a 20-inch barrel holds 6 rounds in the tube magazine plus 1 in the chamber, for a total capacity of 7 rounds.

Is this shotgun suitable for a beginner shooter?

Yes. The pump action is straightforward to operate, the recoil pad helps manage kick, and the ambidextrous safety makes it easy for both left- and right-handed beginners. Start with light target loads to build confidence.

Trust and Convenience

✅ Nationwide delivery to all 50 states
✅ Ships within 1–2 business days
✅ 30-day return policy
✅ Secure checkout with encrypted payment

Last updated: April 2026

According to industry data, pump-action shotguns account for over 40% of all shotgun sales in the U.S., and the Mossberg 590 series is one of the top-selling models in that category.

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