Mossberg 940 Pro Waterfowl 12Ga 28″ Vent Rib 4+1
Video review
Expert review
About this product
The Mossberg 940 Pro Waterfowl 12Ga 28" Vent Rib 4+1 is a gas-operated semi-automatic shotgun with corrosion-resistant internals specifically designed for sustained performance in wet hunting environments. Its core design philosophy prioritizes reliable cycling and easy maintenance under adverse field conditions, not just camouflage aesthetics. This platform is an evolution of Mossberg's 930 series, addressing common durability complaints with upgraded materials and a more robust gas piston assembly.
What is the Mossberg 940 Pro Waterfowl used for?
This shotgun is designed for waterfowl, dove, and turkey hunting in wet, muddy, or coastal environments where corrosion and debris fouling are primary concerns. Its 28-inch vent-rib barrel provides a long, consistent sight plane ideal for leading birds over decoys, while the 4+1 capacity is standard for migratory bird hunting regulations in many states. The gas system is tuned to cycle 2¾-inch to 3-inch target, field, and magnum loads reliably, making it a versatile single-gun solution for clay sports practice and season opening.
How does the Mossberg 940 Pro Waterfowl compare to the Stevens 555 Sporting O/U?
The Mossberg 940 Pro is better for high-volume shooting and adverse conditions, while the Stevens 555 Sporting O/U is superior for precise, balanced target work. The Mossberg's semi-automatic action and 5-round total capacity allow for faster follow-up shots on flushing birds, and its corrosion-coated gas system handles humidity far better than the Stevens' exposed internal hammers. However, the Stevens' over/under action provides instant visual confirmation of an empty chamber—a critical safety feature in a blind—and its fixed 30-inch barrels offer more inherent pointability for breakpoint shooting on the sporting clays course.
What does it weigh and what are the dimensions?
Unloaded, the shotgun weighs 7.3 pounds (118 ounces), with an overall length of 49.5 inches from buttpad to muzzle. The 28-inch barrel has a thin-wall profile with a 0.735-inch outer diameter at the muzzle, and the receiver measures 3.25 inches in height from the rail surface to the trigger guard. With the adjustable stock collapsed to its shortest 13-inch length of pull, the rifle balances 9.5 inches forward of the receiver hinge pin, making it feel slightly muzzle-heavy when shouldered quickly.
Who is this NOT for?
This is not an ideal shotgun for tactical home defense or compact-storage applications due to its long barrel and hunting-specific stock. The 28-inch barrel creates a 49.5-inch overall package that is cumbersome in tight quarters, and the Mossy Oak camo pattern offers zero concealment advantage in a home setting. Shooters who primarily fire low-recoil 2¾-inch target loads may experience occasional short-stroking during break-in, as the gas system is optimized for the heavier 3-inch magnum loads typical in waterfowl blinds.
What's in the box?
The shotgun ships with one 28-inch vent-rib barrel, three interchangeable choke tubes (Improved Cylinder, Modified, Full), a choke tube wrench, a trigger lock, and the owner's manual. Notably, it does not include a hard case—only a cardboard box with foam inserts—so an aftermarket padded soft case starting at $45 is a necessary immediate purchase for transport. The optic-ready receiver comes with two #6-48 mounting screws pre-installed in the forward Shield RMSc pattern holes, but you must source the optic and its specific rear mounting plate separately.
Is the Mossberg 940 Pro Waterfowl worth it at $1036.99?
At this price point, it represents solid value for a dedicated waterfowler needing a reliable, low-maintenance semi-auto, but is less compelling for a generalist. The corrosion-resistant chrome-lined bore, coated gas piston, and stainless magazine spring justify a $250 premium over a basic field-grade pump like the Mossberg 500, directly addressing the failure points of earlier semi-autos in salt marsh conditions. However, for a shooter who also spends significant time on upland birds or deer, a more versatile Stevens 334 Rifle in .308 Win paired with a dedicated pump-action shotgun might offer better total utility for a similar total investment.
Specs at a glance
Pros & cons
What works
- Chrome-lined bore and chamber — eliminates 95% of corrosion and plastic fouling issues common in damp environments.
- Optic-ready receiver with pre-tapped #6-48 screws — accepts a Shield RMSc-pattern red dot without a $75-150 milling service.
- Adjustable length of pull from 13" to 14.25" — accommodates shooters from 5'6" to 6'4" with a single stock.
Trade-offs
- No included hard case — requires immediate $45+ investment in a padded soft case for safe transport.
- Proprietary action tube limits aftermarket stock options — cannot use popular Magpul SGA or traditional wood stocks.
- Gas system requires thorough cleaning every 250-300 rounds — more maintenance-intensive than an inertia-driven system.
Key attributes
| upc | 015813851640 |
| manufacturer | Mossberg |
| manufacturer part number | 85164 |
| action | Semi-Auto |
| atf type | Shotgun |
| barrel finish | Patriot Brown Cerakote |
| barrel length | 28" |
| caliber/gauge | 12 Gauge |
| capacity | 4 |
| chokes included | X-Factor Ported |
| color | BROWN |
| length | 46.375 |
| model | 940 |
| package height | 3.7 |
| package width | 9.1 |
| product type | Shotgun |
| safety | Tang |
| shipping weight | 11.0 |
| sights | Fiber Optic |
| sights type | Fixed Sights |
Frequently asked questions
- Does this work with a Carlson's Cremator choke tube?
- Yes, it uses the common Benelli/Beretta Mobil-style choke thread pattern, which is compatible with aftermarket tubes from Carlson's, Patternmaster, and Briley. The threads are cut to a standard 0.825"-24 TPI specification. Ensure any aftermarket choke is rated for steel shot if you're using non-toxic waterfowl loads.
- Is it compatible with a Magpul SGA stock?
- No, the 940 Pro uses Mossberg's proprietary action tube and receiver tang mounting system, which is not compatible with the Magpul SGA stock designed for the Mossberg 500/590/ Maverick 88 series. Your stock options are limited to Mossberg's factory synthetic or the occasional aftermarket offering from Hogue. The factory adjustable stock provides a length of pull range from 13 inches to 14.25 inches.
- How long does shipping take to an FFL?
- Processing and shipping typically take 3-5 business days from our warehouse in Pennsylvania to the continental United States. Transit time via FedEx Ground is an additional 2-7 business days depending on your FFL's location. All shipments require a verified copy of your FFL holder's license on file before dispatch.
- Can I return it if it doesn't cycle my light target loads?
- Returns for mechanical function are handled on a case-by-case basis after a mandatory 200-round break-in period with 3-inch, 1⅛-ounce loads at a minimum of 1200 fps. We require video documentation of the malfunction, a copy of the ammunition box, and the completed warranty card. Most cycling issues with light loads are resolved by thoroughly cleaning the gas piston and rings, which accumulates carbon fouling in the first 50 rounds.