The Mossberg 590RM is a pump-action shotgun chambered in 12 gauge with an 18.5-inch barrel. It is magazine-fed, using a detachable 10-round box magazine rather than the traditional tube found on standard 590 variants. A 2.75-inch chamber, flat profile trigger, and adjustable stock are noted across listings, with a matte black finish on most configurations. 
 

Key Specifications 

• Brand: Mossberg 
• Model: 590RM 
• Caliber: 12 Gauge 
• Action: Pump Action 
• Capacity: 10+1 
• Barrel Length: 18.5 inches 
• Color/Finish: Black 
   

Detailed Features 

• Detachable 10-round box magazine feed system 
• 18.5-inch barrel in a stand-off configuration 
• 2.75-inch chamber 
• Adjustable stock 
• Compatible with Magpul MBUS 3 sights on equipped variants

The 590RM draws consistent interest from users who want magazine-fed pump-action capability. The detachable box magazine system is the main talking point; owners who run it for patrol or home defense value the faster reload compared to tube-fed designs. The common complaint is that 12-gauge box magazines are bulkier than tube-fed configurations to stage and store.

Pump reliability on the 590RM is generally well-regarded, and owners credit Mossberg's track record with the 590 platform. The 18.5-inch barrel and stand-off configuration handle close-quarters roles without issue. The adjustable stock gets positive marks from users running the shotgun with body armor or in vehicle configurations.

The 590RM costs noticeably more than standard tube-fed 590 variants, and opinions divide on whether the magazine-fed capability is worth the price difference. Magazine availability and cost draw recurring complaints in owner discussions. Those with a specific operational need for fast detachable-magazine reloads find the platform worth the investment; casual users often conclude the standard 590 serves better at lower cost.