The Mossberg 940 JM Pro is a 12-gauge semi-automatic shotgun with a 24-inch barrel and 9+1 capacity. It's designed around competitive shooting — Jerry Miculek had direct input into the feature set. The clean-running gas-vent system cycles reliably under varied conditions and ammo types, which matters in matches where you can't control what's available. 
 

Key Specifications 

• Model: 940 JM Pro 
• UPC: 015813851138 
• Gauge: 12 GA 
• Action Type: Semi-Automatic 
• Chamber Size: 3" 
• Capacity: 9+1 rounds 
• Barrel Length: 24" 
• Overall Length: 44.75" 
• Weight: 7.75 lbs. 
• Finish: Matte Blued Receiver, Black Multicam Stock/Handguard 
   

Detailed Features 

The quick-empty magazine release and quad-loading-optimized design keep reloads fast during competition. Adjustable length of pull ranges from 13" to 14.25", so different-sized shooters can fit the gun without a spacer kit search. The receiver is drilled and tapped for optics mounting, and Briley choke tubes come included for pattern flexibility. 
 
At 7.75 lbs and 44.75" overall, the 940 JM Pro is not light, but the weight helps absorb recoil during extended strings. The MultiCam stock and handguard hold up in outdoor conditions. 
 

Usage Scenarios 

• Competitive 3-gun and shotgun-specific events where the reload speed and reliable cycling are direct performance factors. 
• Home defense where the 9+1 capacity and semi-auto action suit demanding scenarios. 
• Range training with varied loads, where the gas system's tolerance for different ammunition is a practical advantage.

The Mossberg 940 JM Pro gets broadly positive feedback from competitive shooters. The cycling reliability is the most consistent praise — owners report minimal jams across different load types, which is exactly what you need in a match. The MultiCam finish also gets positive remarks for outdoor aesthetics and durability.

Weight is the most common criticism. At 7.75 lbs, some owners find extended carry or all-day matches tiring. A few shooters have also mentioned wanting more aftermarket customization options beyond what ships from the factory. Overall the reception leans positive, with most owners treating the weight as a manageable tradeoff against the cycling performance.