Winchester SX4 20 Gauge 24-inch Synthetic Semi-Auto Shotgun
About this product
The Winchester SX4 20 Gauge 24-inch Synthetic Semi-Auto Shotgun is a gas-operated field shotgun designed for hunters who demand reliability in varied conditions without excessive weight. It’s built on a lightweight aluminum receiver and uses a rotating bolt head like a modern sporting rifle. The 24-inch barrel is a compromise between swing speed in brush and pellet pattern density at range.
What is the Winchester SX4 20 Gauge used for?
This shotgun is used for upland bird and light waterfowl hunting where quick handling and high-volume shooting are required. The 20-gauge chambered for 3-inch shells strikes an optimal balance between manageable recoil for prolonged shooting sessions and sufficient power for pheasant, quail, and dove within 40 yards. It’s not an ideal tool for turkey hunting beyond 50 yards or for dedicated trap shooting where longer barrels dominate.
How does the Winchester SX4 20 Gauge compare to the Stevens 555 Sporting 20 Gauge?
The SX4 is better for sustained rapid fire and varied ammunition, while the Stevens 555 Sporting 20 Gauge O/U offers superior precision for deliberate, two-shot opportunities. The SX4's semi-automatic gas system reduces felt recoil by approximately 30% compared to a fixed-breech O/U like the Stevens, allowing faster follow-up shots on flushing coveys. However, the Stevens’s 30-inch barrel and fixed chokes provide more consistent patterns for sporting clays, making it a better choice for the range.
What does it weigh and what are the dimensions?
The shotgun weighs 6.5 pounds (104 ounces) and measures 45.5 inches in overall length with its 24-inch barrel. The length of pull is 14.25 inches, and the barrel’s internal diameter at the muzzle is 0.615 inches. For context, that’s 1.3 pounds lighter and 5.5 inches shorter than the 30-inch-barreled Stevens 555 Sporting O/U, making it noticeably quicker to shoulder in thick cover.
Who is this NOT for?
This is not for shooters who exclusively fire high-brass 3-inch magnum waterfowl loads or require a dedicated home-defense tool. The gas system is tuned for a mix of 2.75-inch and 3-inch field loads; constant use of maximum-pressure 1.5-ounce waterfowl loads can accelerate wear on the piston rings. For a dedicated home-defense role, its 24-inch barrel is unnecessarily long and slow to maneuver indoors compared to an 18.5-inch cylinder-bore shotgun.
What's in the box?
The box contains the assembled shotgun, three Invector-Plus choke tubes (Improved Cylinder, Modified, Full), a choke tube wrench, and an owner’s manual. Unlike some competitors, it does not include a hard case—expect a cardboard shipping box with foam inserts. You’ll need to purchase a separate case, which adds approximately $40-$75 to the total setup cost.
Is the Winchester SX4 20 Gauge worth it at $967.99?
At $967.99, it’s worth it for hunters who shoot over 500 shells per season and value reduced recoil fatigue and reliable cycling above all else. This price point is justified by the hard-chrome bore, corrosion-resistant finish, and the proven Active Valve gas system that cycles target loads as light as 7/8 ounce. For a casual shooter who fires fewer than 100 shells a year, a pump-action or a used semi-auto like a Beretta A300 at around $700 represents a more cost-effective entry point.
Specs at a glance
Video review
Pros & cons
What works
- Weighs 6.5 lbs (104 oz) — 1.3 lbs lighter than a comparable 12-gauge model for less fatigue.
- Hard chrome-plated bore resists corrosion 3-4x longer than a plain carbon steel barrel.
- Active Valve gas system cycles light 7/8 oz target loads up to heavy 1.5 oz magnums without adjustment.
- Inflex recoil pad reduces perceived recoil by an estimated 20% versus a basic rubber pad.
Trade-offs
- No factory optics rail — requires gunsmith drilling/tapping ($75-$150) for red dot mounting.
- Stock is not length-adjustable; shorter-statured shooters may need a $30 spacer kit.
- Synthetic forend has minimal texture — aggressive handling may benefit from added grip tape.
- Does not include a hard case, adding $40-$75 to the total cost of ownership.
Expert review
Key attributes
| upc | 048702009945 |
| manufacturer | Winchester |
| manufacturer part number | 511205690 |
| package width | 9.5 |
| package height | 3.3 |
| shipping weight | 9.0 |
| sights | TruGlo Fiber Optic Front |
| sights type | Fixed Sights |
| product type | Shotgun |
| capacity | 3 + 1 |
| caliber/gauge | 20 Gauge |
| atf type | Shotgun |
| barrel length | 24" |
| action | Semi-Auto |
Frequently asked questions
- Is the Winchester SX4 compatible with aftermarket choke tubes?
- Yes, but only with Winchester Invector-Plus pattern tubes. The threads are proprietary and different from the standard Invector or Beretta Mobil patterns. Browning, which is owned by the same parent company, also uses Invector-Plus, so some Browning-branded chokes will fit. Do not attempt to force a different pattern tube into the muzzle.
- Does this shotgun fit in a standard 48-inch rifle case?
- Yes, with room to spare. With an overall length of 45.5 inches, it will fit easily into most 48-inch takedown cases. For a more secure fit with chokes and accessories, consider a 52-inch hard case from brands like Plano or Pelican.
- How long does shipping take for this firearm?
- Shipping to your selected FFL dealer typically takes 3-7 business days once the order is processed and your FFL information is verified. Processing itself takes 1-2 business days. You will receive a tracking number once the shipment is in transit with our carrier, usually FedEx.
- Can I mount an optics rail on this receiver?
- The receiver is not drilled and tapped for an optics rail from the factory. A competent gunsmith can drill and tap the aluminum receiver to accept a Picatinny rail for approximately $75-$150 in labor. The synthetic stock's comb height is not designed for optics, so you may also need an aftermarket cheek riser.
- Does this work with Aguila mini-shells?
- No, it will not cycle Aguila 1.75-inch mini-shells reliably. The minimum recommended shell length for reliable function in this gas-operated system is 2.75 inches (67mm). Attempting to cycle shorter shells will almost certainly result in failures to feed and eject.