WGUN 511331692 SX4 WTFL MOOSG, 20-3, 28 INV+
Pros & cons
What works
- Cerakote finish provides superior corrosion resistance for salt marsh environments.
- Active Valve gas system self-regulates for loads from 2¾-inch 7/8 oz to 3-inch 1¼ oz without adjustment.
- Weighs 6.8 lbs — balances the 28-inch barrel well for sustained tracking on waterfowl.
- Includes 3 Invector-Plus choke tubes (F, M, IC), covering most waterfowl and upland scenarios.
Trade-offs
- Online Only — requires FFL transfer, adding $25-50 and a wait versus in-store purchase.
- Gas system requires more detailed cleaning after a wet day than an inertia-driven or break-action gun.
- No sling included — a notable omission for a waterfowl gun priced over $1,100.
- 28-inch barrel can be less maneuverable in tight layout blinds compared to a 26-inch model.
Video review
Expert review
Specs at a glance
About this product
What is the Ironclad Armory WGUN 511331692 SX4 WTFL MOOSG? This is the Winchester SX4 Waterfowl shotgun, a 20-gauge, 3-inch chamber semi-automatic designed for extreme marsh conditions, built around the proven Active Valve gas system and including a 28-inch ported barrel and three Invector-Plus choke tubes.
What is the Winchester SX4 used for?
This shotgun is engineered for waterfowl hunting in marshes and other wet, punishing environments. Its cerakote finish resists corrosion, the ported 28-inch barrel aids in managing recoil with heavy waterfowl loads, and the Active Valve system cycles high-brass 2¾-inch quail loads to 3-inch steel shot without manual adjustment, making it a versatile tool for a full season.
How does the SX4 compare to the Stevens 555 Sporting O/U?
The SX4 is a purpose-built, high-volume waterfowl semi-auto, while guns like the Stevens 555 Sporting O/U 20 Gauge are better for clays or upland hunting. The SX4’s gas system reduces perceived recoil by an estimated 30% compared to an over-under’s fixed breech, a critical advantage when firing dozens of 3-inch shells in a morning, but it will be heavier and require more field stripping for cleaning than a break-action shotgun.
What does it weigh and what are the dimensions?
The SX4 Waterfowl model weighs 6.8 pounds unloaded and measures 48.5 inches overall with its 28-inch barrel. The length of pull is 14.375 inches, and the chrome-plated chamber is 3 inches long, accommodating everything from light target loads to heavy waterfowl and turkey ammunition.
Who is this NOT for?
This is not the gun for a hunter primarily focused on upland birds or casual trap shooting. Its 28-inch barrel and waterfowl-specific camo make it cumbersome in dense cover compared to a 26-inch field model, and the gas system, while reliable, requires more detailed cleaning than the simpler inertia system found in some competitors or a break-action like the Stevens 555.
What's in the box?
You receive the shotgun with three Invector-Plus choke tubes (Full, Modified, Improved Cylinder), sling swivel studs installed, and a set of choke tube wrenches. The gun ships with a manual and a cable lock, but does not include a sling; you’ll need to add your own, a common oversight we detail in our SX4 field maintenance guide.
Is the Winchester SX4 worth it at $1,132.99?
At just over $1,100, the SX4 Waterfowl sits in a competitive bracket above entry-level pumps but below premium semi-autos. Its value lies in the tested Active Valve system’s reliability—a system that has seen over a million rounds of testing—and its corrosion-resistant finish. For a dedicated waterfowler who needs a gun that will cycle reliably in freezing rain and muddy blinds, it’s a justifiable investment. For someone who hunts ducks only a few times a year, a less expensive pump-action may represent better value.
Key attributes
| upc | 048702028328 |
| manufacturer | Winchester |
| manufacturer part number | 511331692 |
| action | Semi-Auto |
| barrel length | 28" |
| caliber/gauge | 20 Gauge |
| capacity | 4 + 1 |
| chokes included | Full/Improved Modified/Modified |
| color | CAMOFLAGE |
| product type | Shotgun |
| safety | Crossbolt |
| shipping weight | 0.0 |
| sights | TruGlo Fiber Optic |
| sights type | Fixed Sights |
Frequently asked questions
- Is it compatible with standard Invector choke tubes?
- No, it uses Winchester's Invector-Plus threading, which is not backward compatible with older standard Invector chokes. The gun ships with the three essential tubes (Full, Modified, IC) and additional specialized chokes are available from manufacturers like Carlson's or Briley.
- Does it fit in a standard 52-inch shotgun case?
- Yes, the 48.5-inch overall length allows it to fit comfortably in a standard case with room for accessories. We recommend a hard-sided, water-resistant case like those from Plano All-Weather for extended transport to the marsh.
- How long does shipping take for an online-only firearm?
- Firearm shipments require processing through a licensed FFL dealer. After order verification (typically 1-2 business days), the firearm ships via 2-3 day air to your selected FFL, where you will complete the required Form 4473 and background check before taking possession.
- Can I return it if it doesn't cycle my light target loads?
- Firearms are generally non-returnable once transferred due to federal regulations. However, the SX4's Active Valve is designed to cycle a wide range from 2¾-inch target loads to 3-inch magnums. If you experience issues, contact Winchester's customer service for warranty evaluation; they typically require the firearm to be inspected by an authorized service center.