The Mossberg 940 JM Pro is a 12 GA semi-automatic shotgun with a 24-inch vent rib barrel and Tungsten Gray finish. It holds 9+1 rounds with a 3-inch chamber and weighs 7.75 lbs. 
 

Key Specifications 

• Model: 940 JM Pro 
• UPC: 015813851657 
• Action Type: Semi-Automatic 
• Caliber/Gauge: 12 GA 
• Barrel Length: 24 inches 
• Capacity: 9+1 rounds 
• Weight: 7.75 lbs. 
• Chamber Size: 3 inches 
• Finish: Tungsten Gray 
   

Detailed Features 

The vent rib barrel disperses heat during sustained shooting and aids in maintaining a consistent sight picture. HiViz CompSight fiber optic sights provide fast target acquisition. The length of pull is adjustable from 13" to 14.25", which lets the gun fit a range of shooter sizes without adding a stock. The synthetic stock is weather-resistant and light. 
 

Usage Scenarios 

The 9+1 capacity and fast cycling action make this a natural fit for 3-gun competition. It also works for hunting applications where a lighter 12-gauge with a shorter barrel is preferred. The adjustable LOP is particularly useful when multiple shooters share the gun.

The 940 JM Pro gets consistent praise for its smooth cycling action and reliable operation under competition conditions. Ergonomics and stock adjustability come up as positives. The Tungsten Gray finish gets compliments for looking different from the standard black.

Some users mention initial break-in or jamming issues with specific ammo -- this seems to resolve once the gun is properly run in. Generally, owners recommend it for anyone who wants a reliable semi-auto at a price below the top-tier competition guns.