The Citadel Mariner is a pump-action shotgun chambered in 20 Gauge with a 3-inch chamber. It has an 18.50-inch nickel-finished barrel fitted with a heat shield, a nickel-finished aluminum receiver, and a Picatinny rail. This variant ships with a black fixed walnut stock in place of synthetic, and capacity is 4+1 rounds. 
 

Key Specifications 

• Brand: Citadel 
• Model: Mariner 
• Caliber: 20 Gauge 
• Action: Pump Action 
• Capacity: 4+1 
• Barrel Length: 18.50 in 
• Color/Finish: Nickel 
   

Detailed Features 

• 18.50-inch nickel-finished barrel with heat shield 
• Nickel-finished aluminum receiver 
• Picatinny rail for optic or accessory mounting 
• Black fixed walnut stock 
• 3-inch chamber

Owners who pick the walnut-stock Mariner over the synthetic variant typically mention aesthetics as the deciding factor. The nickel and walnut combination is seen as a cleaner look at a budget price point, and several owners report it turns heads at the range.

The same corrosion-resistance praise that follows the synthetic model applies here. Nickel over the receiver and barrel inspires confidence in humid environments, though some owners note the walnut stock has no protective finish applied from the factory and benefits from a coat of oil.

Action smoothness improves after a few hundred rounds for most owners. The trigger is serviceable but not refined, which is consistent feedback across the Mariner line regardless of stock material.