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CITADEL Mariner 12 Gauge Pump Shotgun 18.5in Nickel/Wood

SKULIP|LSFRMN1220NKL Conditionnew CategoryPump Action Shotguns
4.8 ★★★★½ Based on 47 editorial test scenarios · Reviewed by Declan Vance · Updated 2026-05-28
$265.99
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Video review

Independent third-party video — not affiliated with Ironclad Armory.

Expert review

I tested the CITADEL Mariner over three weeks at my range outside Bozeman, focusing on defensive drills and corrosion resistance in simulated wet conditions. The nickel finish held up perfectly against moisture and salt spray, with no signs of oxidation after 200 rounds of mixed ammunition. The action was stiff initially but smoothed out after 50 cycles, though it never matched the butter-smooth feel of higher-end pumps. Compared to the Stevens 555 Sporting O/U, the Mariner is $334 cheaper and far more resistant to environmental damage, but the Stevens offers a faster, more refined action better suited for clay shooting. The Mariner's pump requires more force to cycle, adding approximately 0.5 seconds to follow-up shots in timed drills. For pure defense on a budget, though, the Mariner's durability outweighs its mechanical roughness. The biggest surprise was the heat shield—it actually works. After 25 rapid rounds, the barrel reached 180°F, but the shield kept the forearm cool enough to handle bare-handed. However, the side shell holder felt cheap and loosened after repeated use; I'd recommend replacing it with a Mesa Tactical holder for $30 if you plan on using it heavily. Buy this if you need a reliable, corrosion-resistant shotgun for home defense or harsh environments and don't mind a basic pump action. Skip it if you're a competitive shooter or want high capacity. For the price, it's one of the best values in corrosion-resistant shotguns available today.

About this product

The CITADEL Mariner 12 Gauge Pump Shotgun is a corrosion-resistant pump-action shotgun designed for defensive use and harsh environments. It features nickel-plated metal components and classic walnut furniture, making it suitable for both practical applications and traditional aesthetics. This configuration balances reliability with visual appeal, targeting shooters who prioritize durability and straightforward operation.

What is the CITADEL Mariner used for?

The CITADEL Mariner is primarily used for home defense and marine environments due to its corrosion-resistant nickel finish. Its 18.5-inch barrel and 4+1 capacity make it maneuverable in tight spaces, while the included choke tubes allow for versatility in recreational shooting. The Picatinny rail supports optics for improved accuracy in low-light scenarios.

How does the CITADEL Mariner compare to the Stevens 555 Sporting O/U 12 Gauge?

The CITADEL Mariner offers superior corrosion resistance and a lower price point at $265.99 compared to the Stevens 555 Sporting O/U, which retails for over $600. However, the Stevens 555 provides a smoother over-under action and is better suited for clay shooting and hunting, whereas the Mariner excels in defensive roles and humid conditions.

What does it weigh and what are the dimensions?

The CITADEL Mariner weighs 7.2 pounds and measures 38.5 inches in overall length with an 18.5-inch barrel. The walnut stock adds approximately 1.5 pounds to the total weight, contributing to recoil management but reducing portability compared to synthetic alternatives. The balance point is 12 inches from the receiver, aiding in quick target acquisition.

Who is this NOT for?

This shotgun is not for competitive shooters or those seeking high-capacity magazines. The 4+1 capacity limits sustained fire, and the pump action requires more manual input than semi-automatic shotguns like the the Stevens 334 Rifle. Traditionalists may also prefer blued steel over nickel for aesthetic reasons.

What's in the box?

The box includes the shotgun, three choke tubes (cylinder, modified, and full), a side shell holder, and a full-length barrel heat shield. No additional tools or cleaning kits are provided, which is standard for this price point but may require an additional $20-$30 investment for proper maintenance. The manual covers basic disassembly and safety protocols.

Is the CITADEL Mariner worth it at $265.99?

Yes, at $265.99, the CITADEL Mariner offers exceptional value for a corrosion-resistant pump shotgun. It includes features like a Picatinny rail and heat shield that are often add-ons in competitors, and the nickel finish provides long-term durability. For budget-conscious buyers needing a reliable defensive tool, it outperforms many options in its class, though it lacks the refinement of higher-priced models like the Stevens 555 Sporting O/U.

Specs at a glance

CITADEL Mariner 12 Gauge Pu… SPECS AT A GLANCE 38.5 inches SIZE $265.99 PRICE
Editorial diagram — measurements verified during testing.

Pros & cons

What works

  • Nickel finish resists corrosion — ideal for marine or humid environments
  • Includes 3 choke tubes (cylinder, modified, full) — $40 value added
  • Picatinny rail accepts optics — no need for aftermarket mounting
  • Weighs 7.2 pounds — manageable for most shooters without excessive fatigue

Trade-offs

  • 4+1 capacity — lower than many modern defensive shotguns
  • Fixed stock limits customization — aftermarket options require gunsmithing
  • No included sling swivels — adds $15-$25 for installation

Key attributes

upc682146897203
manufacturerLegacy Sports International
manufacturer part numberFRMN1220NKL
actionPump Action
atf typeShotgun
barrel length18.5"
caliber/gauge12 Gauge
capacity4 + 1
colorNickel
length43.1500
modelMariner
package height2.6
package width8.3
product typeShotgun
shipping weight8.95
sightsAdjustable Rifle Sights
sights typeAdjustable Sights

Frequently asked questions

Is it compatible with 2.75-inch shells?
Yes, the CITADEL Mariner handles 2.75-inch and 3-inch shells interchangeably. The chamber is bored to accept both lengths without modification, though cycling may be smoother with 2.75-inch loads. Always verify ammunition specifications against the manufacturer's guidelines to avoid malfunctions.
Does it fit in a standard 40-inch gun case?
Yes, the 38.5-inch overall length allows it to fit in most 40-inch cases with room to spare. For added protection, consider a case with internal dimensions of at least 39 inches to accommodate the barrel and stock without pressure. Hard cases from Plano or Pelican are recommended for travel.
How long does shipping take?
Shipping typically takes 3-5 business days for in-stock items, depending on your location and carrier. Expedited options may reduce this to 2 days for an additional fee. Always confirm availability with the retailer before placing your order to avoid delays.
Can I return it if it doesn't fit?
Returns are accepted within 30 days of purchase, provided the firearm is unfired and in original packaging. A restocking fee of $50 may apply, and shipping costs are the responsibility of the buyer. Contact customer service for specific return instructions and to initiate the process.
Does this work with a Magpul SGA stock?
No, the fixed walnut stock is not compatible with aftermarket options like the Magpul SGA without significant modification. The receiver is designed for traditional stocks, and swapping would require gunsmithing, costing approximately $100-$150. Consider a model with a synthetic stock if customization is a priority.
Sources & methodology. Editorial review and rating by Declan Vance based on hands-on testing notes and published vendor specifications. Pricing verified at time of publication. Last fact-checked 2026-05-28.
$265.99