The Mossberg 940 JM Pro is a 12-gauge semi-automatic shotgun designed in collaboration with competitive shooter Jerry Miculek for 3-gun and speed shooting applications. The 9+1 capacity and 24-inch barrel, paired with the Hiviz Compsight fiber-optic sights and optics-ready receiver, make the competition focus explicit from the start. 
 

Key Specifications 

• SKU: 2024900872 
• UPC: 015813851664 
• Brand: Mossberg 
• Model Name: 940 JM Pro 
• Chamber Size: 3" 
• Action Type: Semi-Auto 
• Capacity: 9+1 rounds 
• Barrel Length: 24" 
• Overall Length: 44.75" 
• Weight: 7.75 lbs. 
• Sights: Hiviz Compsight Fiber Optic (Optic-ready) 
• Grip Type: Standard 
• Trigger Type: Standard 
• Safety Feature: Top Tang Safety 
• Finish Color/Pattern: Digital Camouflage 
   

Detailed Features 

 
The adjustable length of pull runs from 13 to 14.25 inches via stock spacers, covering most adult shooter sizes. The Hiviz Compsight fiber-optic system is among the brighter competition sighting options available on a factory shotgun. The optics rail allows mounting a red dot without modification. Briley extended chokes are included (a competition-grade upgrade over standard factory chokes). The digital camouflage MultiCam finish covers the synthetic stock. 
 
At 7.75 lbs with a 44.75-inch overall length, this is a full-size gun designed for standing courses of fire rather than hiking.

Competition shooters who use the 940 JM Pro consistently note the high round capacity and smooth gas-operated cycling as the gun's main strengths. The 9+1 capacity is specifically called out as a differentiator for 3-gun stages where magazine tube extensions would otherwise be needed.

The Briley chokes are appreciated as a meaningful factory upgrade. The Hiviz sights draw positive mentions for visibility. The adjustable LOP is valued by shooters who want a precise fit for fast mounts.

Ease of cleaning comes up regularly as a positive -- the gas system is designed for simpler disassembly than older semi-auto platforms.

Recoil management is generally noted as good for heavy competition loads. Price relative to competitors is discussed, with most buyers concluding the competition-specific features justify the cost for serious 3-gun use. Owners who want it for hunting or defense sometimes note that lighter or more compact options might suit those roles better.