The Mossberg 590A1 is a 12 GA pump-action shotgun built around a heavy-walled barrel and a Marinecote finish that resists corrosion in hard conditions. It holds 6 rounds plus 1 in the chamber, runs an 18.5" barrel, and has a 3" chamber. Weight is 7 lbs with a black synthetic fixed stock. The bead front sight keeps things simple for fast target acquisition. The Marinecote receiver and heavy-walled barrel are the spec differences that set the 590A1 apart from standard 590 models. 
 

Key Specifications 

• Brand: Mossberg 
• Model: 590A1 
• UPC: 015813507677 
• Gauge: 12 GA 
• Action: Pump Action 
• Capacity: 6 Rounds + 1 Chambered 
• Barrel Length: 18.5 inches 
• Chamber Size: 3 inches 
• Weight: 7 lbs. 
• Finish: Black synthetic stock with Marinecote receiver

The 590A1 has a strong reputation for reliability and build quality. Users regularly point to its military-grade construction, the heavy-walled barrel, and the Marinecote finish as reasons they trust it for home defense and hard use. Pump action operation is called smooth and intuitive, even under stress.

The gun accepts a wide range of accessories, and many owners customize it with lights, slings, and aftermarket stocks.

Criticism tends to focus on weight: at 7 lbs it's heavier than some alternatives in its class, which matters for extended carry. Recoil with 12 GA loads can be stout for shooters new to shotguns. A few users would prefer more stock options out of the box, and price occasionally comes up as a consideration against budget pump guns.