The Mossberg 590 Tactical is a 12-gauge pump-action shotgun with an 18.5-inch barrel and a FLEX adjustable synthetic stock. The FLEX system lets you swap length-of-pull between roughly 10.75" and 14.25" by swapping the stock component, which makes it a practical fit for different shooters or shooting positions. 
 

Key Specifications 

• SKU: 3457615 
• UPC: 015813506915 
• Brand: Mossberg 
• Model Name: 590 Tactical 
• Action Type: Pump Action 
• Caliber/Gauge: 12 GA 
• Capacity: 6 + 1 rounds 
• Chamber Size: 3" 
• Barrel Length: 18.5" 
• Overall Length: 31" to 36.37" (adjustable) 
• Weight: Approximately 6.75 lbs. 
• Sights: Bead Front Sight 
• Stock Finish: FLEX Adjustable Synthetic (Black) 
   

Features 

 
The matte blued finish is durable without being reflective. The cylinder bore choke is appropriate for defensive use at close to medium distances. The top-tang safety is operable without breaking your grip or shifting hand position, which is a consistent preference in the Mossberg line. 
 
The 6+1 capacity in a compact 18.5-inch package makes it maneuverable in confined spaces. Aftermarket FLEX system accessories are widely available for further stock customization.

Owners of the 590 Tactical with the FLEX stock generally give it good marks for reliability and durability. The Mossberg pump action cycles reliably with a wide range of loads, and the dual action bars contribute to that. The FLEX adjustable stock is frequently cited as one of the more useful features -- being able to change length-of-pull without tools or additional parts is genuinely practical.

Ergonomics are described as comfortable, and the top-tang safety placement is appreciated for staying accessible without grip adjustment. At around 6.75 lbs. the balance is acceptable for a defensive shotgun of this configuration.

Some users note the bead front sight is minimal and prefer a ghost ring or rifle sight configuration for more precise aiming. Weight in extended carry situations is occasionally mentioned. Aftermarket support for the FLEX system is seen as a positive -- the modular stock design opens up customization options without requiring full stock replacements.