Mossberg 940 Pro Field 12ga 28in Vent Rib 4+1
Pros & cons
What works
- 1.25 inches of LOP adjustment—fits a wider range of shooters without aftermarket stocks.
- Corrosion-resistant internals rated for up to 1,500 rounds between cleanings in field conditions.
- Weighs 7.75 lbs—balances forward for a smooth swing on a 28-inch barrel.
- Includes three Accu-Set chokes (F, M, IC) covering most hunting and clay applications.
Trade-offs
- Right-hand controls only—no ambidextrous option for left-handed shooters.
- Does not include a mandatory 2-round magazine plug for waterfowl hunting.
- Gas piston system requires more detailed cleaning than a pump or break-action after heavy use.
Video review
Expert review
Specs at a glance
About this product
The Mossberg 940 Pro Field 12ga 28in Vent Rib 4+1 is a gas-operated semi-automatic field shotgun engineered for extended reliability in demanding upland and waterfowl environments over thousands of rounds. It's built with corrosion-resistant internals and an adjustable stock to fit a wide range of shooters. As Mossberg's refined successor to the 930 series, this model represents a focused investment in durability and shooter ergonomics.
What is the Mossberg 940 Pro Field used for?
This shotgun is used for upland bird hunting, waterfowling, and sporting clays where sustained firing schedules and adverse conditions are expected. Its 28-inch vent-rib barrel provides a smooth, consistent swing plane for wingshooting, while the gas system is tuned to cycle a wide range of 2¾” and 3” 12-gauge loads without adjustment. The corrosion-resistant coating on internal components like the piston and magazine tube is specifically for hunters who operate in wet, muddy, or brackish environments where maintenance opportunities are limited.
How does the Mossberg 940 Pro Field compare to a Stevens 555 Sporting O/U 12 Gauge 30in?
The Mossberg 940 Pro Field offers greater practical capacity and faster follow-up shots than the break-action Stevens 555 Sporting O/U 12 Gauge. Where the Stevens 555 is a simple, reliable over-under limited to two shells, the 940 Pro Field provides a 4+1 capacity from a tubular magazine, making it significantly better for scenarios like pass shooting at ducks or a long station in a sporting clays course where a fifth shot matters. The trade-off is complexity; the 940's gas system requires periodic cleaning, while the 555's break-action requires almost none.
What does it weigh and what are the dimensions?
Unloaded, the shotgun weighs 7.75 pounds (123.2 oz), with an overall length of approximately 48.5 inches from buttpad to muzzle. The 28-inch barrel features a 0.5-inch-wide vent rib to dissipate heat and reduce mirage. The synthetic stock provides 1.25 inches (31.75 mm) of length-of-pull adjustment, allowing it to fit shooters with pull lengths from 13 inches to 14.25 inches without aftermarket parts.
Who is this NOT for?
This shotgun is not for left-handed shooters, tactical/home defense users, or those seeking absolute minimalist maintenance. All controls, including the tang-mounted safety and shell release, are configured for right-hand operation only. Its 28-inch barrel and field-focused ergonomics make it poorly suited for close-quarters maneuvering compared to an 18.5-inch defensive model. While rated for up to 1,500 rounds between cleanings, it still requires more detailed disassembly than a pump-action or break-action shotgun for proper service.
What's in the box?
You receive the shotgun, three Accu-Set choke tubes (Full, Modified, Improved Cylinder), a choke tube wrench, and the owner's manual. The chokes are the only accessories included; you must purchase a separate case, sling, and additional chokes like a Light Modified or Skeet tube separately. Notably, it does not come with the magazine plug required for hunting migratory birds in most states, which is a 1.5-inch-long polymer dowel you must source independently.
Is the Mossberg 940 Pro Field worth it at $798.99?
At $798.99, it's worth it for the hunter or sport shooter who values proven gas-system reliability, corrosion resistance, and an adjustable stock in a single package. You are paying a premium over a basic pump-action like a Mossberg 500 for the faster cycling and reduced perceived recoil of a semi-auto. Compared to the price of a comparable Benelli or Beretta semi-auto, the 940 Pro Field offers about 85% of the performance for roughly 60% of the cost, making it a high-value workhorse for someone who shoots 500+ shells per season.
Key attributes
| upc | 015813851558 |
| manufacturer | Mossberg |
| manufacturer part number | 85155 |
| action | Semi-Auto |
| atf type | Shotgun |
| barrel finish | Matte Blued |
| barrel length | 28" VR |
| caliber/gauge | 12 Gauge |
| capacity | 4 + 1 |
| chokes included | F,M,IC |
| color | Blue |
| length | 46.375 |
| magazine included | Tubular Magazine |
| model | 940 Pro |
| package height | 3.6 |
| package width | 9.1 |
| product type | Shotgun |
| safety | Ambidextrous Top Tang |
| shipping weight | 10.87 |
| sights | Fiber Optic Front Sight |
| sights type | Fixed Sights |
Frequently asked questions
- Is it compatible with 2.75-inch target loads?
- Yes, it is fully compatible with standard 2¾-inch 12-gauge target loads from 1 oz (dram equivalent 3) up to 1⅛ oz (dram equivalent 3¼) without any adjustments to the gas system. Mossberg specifies the gas piston is self-regulating across this range. For consistently reliable cycling with the lightest 7/8 oz target loads, some users report better performance after a 200-round break-in period.
- Does it fit in a standard 50-inch gun case?
- Yes, with room to spare. With its 48.5-inch overall length, the 940 Pro Field will fit comfortably in most standard 50-inch takedown or soft-sided shotgun cases. For a hardshell case, a model with internal dimensions of at least 49 inches is recommended to prevent the muzzle or buttpad from pressing against the ends during transport.
- How long does shipping take to an FFL?
- For in-stock items, processing takes 1-2 business days, and ground shipping typically adds 3-7 business days transit time to your selected Federal Firearms License (FFL) holder. Total time from order to FFL notification is usually 5-10 business days. You must contact your FFL after ordering to provide them with your order number and ensure they will accept the transfer, which adds a variable of 1.5 days on average.
- Can I return it if it has a mechanical defect?
- Yes, within 30 days of purchase for a full refund or exchange if a mechanical defect is confirmed by our armorers. The firearm must be returned, unfired, in its original packaging with all accessories to our facility via an approved carrier. For defects arising after 30 days, Mossberg's manufacturer warranty, which covers parts and labor for one year from the original purchase date, applies and requires direct contact with Mossberg Customer Service.
- Does this work with aftermarket choke tubes?
- It works with any aftermarket choke tube that uses the Mossberg Accu-Set thread pattern (also known as Mossberg Accu-Choke). This is a different thread pattern than Beretta/Benelli Mobilchoke or Browning Invector. Popular brands like Carlson's, Trulock, and Patternmaster produce Accu-Set compatible chokes. Always confirm the product listing specifies "Mossberg Accu-Set" for the 12-gauge 940 series.
- Is the fiber optic sight replaceable?
- Yes, the front Hi-Viz style fiber optic sight is user-replaceable. It uses a standard .125-inch (1/8-inch) diameter fiber rod, approximately 1.25 inches long, which can be replaced with rods of different colors (green, red, orange, yellow) sold by Hi-Viz Shooting Systems and other accessory retailers. The rod is held in place by two press-fit polymer end caps that can be removed with a small flat-head screwdriver.