The Mossberg 940 Pro Field is a gas-operated semi-automatic shotgun in 12 GA with a 3-inch chamber. This variant ships with an adjustable stock and HiViz CompSight fiber optic sights on a 28-inch barrel, weighing 7.75 lbs at 47.5 inches overall. 
 

Key Specifications 

• Brand: Mossberg 
• Model: 940 Pro Field 
• Caliber: 12 Gauge 
• Action Type: Semi-Auto 
• Capacity: 4+1 rounds 
• Barrel Length: 28 inches 
• Overall Length: 47.5 inches 
• Weight: 7.75 lbs 
• Chamber Length: 3 inches 
• Stock Type: Adjustable 
• Sights: HiViz CompSight Fiber Optic 
   

Detailed Features 

 
The HiViz CompSight fiber optic front sight is a step up from a standard bead — it's brighter in low light and gives a defined reference point for competition shooting or field use where a bead can get lost against busy backgrounds. The adjustable stock handles shim-based length of pull and cast adjustments so the gun fits different shooters without aftermarket work. 
 
The Accu-Set choke system includes full, modified, and improved cylinder chokes for different patterns. The ambidextrous tang safety is accessible from either side. Mossberg's gas system on the 940 Pro is designed to cycle reliably with a wide range of 2-3/4" and 3" loads including light target loads, which is a notable point for skeet and sporting clays use.

The 940 Pro Field with adjustable stock draws favorable feedback for its reliable cycling across different load types, the adjustable stock's versatility for fitting multiple shooters, and ease of operation. Competitive shooters and hunters both find the platform practical.

Weight at 7.75 lbs is noted as heavier than some semi-auto alternatives. Some owners experience a break-in period with lighter loads before the action cycles consistently from the first round. Price is above entry-level semi-auto shotguns, which leads some buyers to compare it against competing models in the same range. Aftermarket customization is less extensive than pump-action platforms.