Review: Winchester Super X4 Cantilever Buck

The Super X4 Cantilever Buck hits all the right points as an accurate, reliable and soft-shooting slug gun.

Review: Winchester Super X4 Cantilever Buck

I’ve had rifles that didn’t shoot this well, I thought to myself as I recovered from recoil of the heavy slug load and saw the small cluster of big holes in the target paper.

Growing up in the Mid-Atlantic region afforded me a lot of experience to draw from when it comes to slugs and slug guns. Not only were slugs the law in some jurisdictions back then, but it turns out that they were eminently practical for places where the vegetation was thick. 

This isn’t because slugs are any kind of “brush buster” (they’re not). The real reason? Shooting distances were short, and a deer that wasn’t anchored swiftly was quickly swallowed up by the brush. If you’ve never shot a big whitetail solidly with a 12-gauge slug, let me tell you, it defines “anchored swiftly.”

The short distances were tailor-made for slug hunting because the guns and loads back then were simply awful when it came to accuracy. We’d debate whether smooth or rifled slugs were more accurate, and whether rifling actually caused the slug to spin (it doesn’t).

Occasionally someone would show up in deer camp with the then-exotic Brenneke-style slugs, which didn’t necessarily shoot any better than the Foster-type, but conveyed a certain sense of superior status.

If you were a real slug-shooting hotshot, you showed up with an Ithaca Deerslayer that really wasn’t any different from our ordinary smoothbores except it had adjustable sights so you could actually aim your shots. 

Slugs and slug guns are a heck of a lot different today. Fully rifled barrels, scope mounts, saboted loads, etc. have all come together to improve the accuracy and performance of slug guns to the point that your only practical limitation could be the terminal ballistics of whatever projectile you’re shooting.

Winchester Super X4 Cantilever Buck
Winchester Super X4 Cantilever Buck

Winchester recently sent me an example of its latest entry into the slug gun market, the semi-auto Super X4 Cantilever Buck, and it has all the features you’d expect in a top-tier slug gun — fully rifled barrel, adjustable iron sights (TruGlo fiber-optic no less), a self-regulating gas system, and its namesake cantilever scope base. Winchester Shooting Promotions Manager Scott Grange calls the SX4 the ideal gun for “the person who is looking for a reliable, pleasant to shoot, accurate slug system that offers quick follow-up shots and will ergonomically accommodate cold weather gear such as bulky gloves.”

The cantilever base is really the key to the kind of accuracy Grange was telling me this slug gun could produce. It’s key because it’s mounted to the barrel, not the receiver. Because of the way most semi-auto and pump-action shotguns are assembled, where you insert the barrel into the receiver and then secure it with the magazine cap, there is always a little play between the barrel and the receiver that are independent of each other, and that can affect accuracy. While there are many very accurate slug guns with scopes mounted on the receiver, they can’t overcome that little bit of play, which is why I believe the cantilever arrangement is superior when it comes to making an accurate repeating slug gun.

The cantilever arrangement on the SX4 is probably the best I’ve ever seen. It mounts really low to the receiver where it’s better protected from damage, and is even low enough for you to use the adjustable flip-up iron sights if you choose. In fact, it’s mounted so low that Winchester put a small rubber buffer on its extension where it goes over the receiver to dampen the amount of vibration that’s delivered to the scope instead of leaving it going like a tuning fork.

Winchester equipped the Super X4 Cantilever Buck with a folding and adjustable rear sight and a TruGlo fiber-optic front.
Winchester equipped the Super X4 Cantilever Buck with a folding and adjustable rear sight and a TruGlo fiber-optic front.

A low mount also helps you take a solid cheek weld when using a scope, and that goes a long way toward making slugs more comfortable to shoot — especially some of the doozie slug loads the ammunition manufacturers are producing these days. “Our customers say the SX4 Cantilever shotgun is the most pleasant-shooting slug gun they’ve ever fired,” Grange said.

And those customers are right — this is one of, if not the, softest shooting slug gun I’ve ever fired and, not discounting the solid cheek weld, there are a couple other reasons for that. One is the self-regulating gas system. Grange tells me it’s a little different from the system used on the Super X3 to better optimize the gas usage. In it, the piston has a very stout spring inside and, when you fire a cartridge, gas bleeds from two holes in the gas block compressing the spring and allowing just enough energy into the system to work the action. The rest of the gas is vented out of slots in the top of the forearm. 

Grange said, “If the system wasn’t self-regulating, lower velocity ammunition would not function properly, while high-velocity or magnum ammunition would deliver too much energy to the bolt, thus creating a violent action and possibly inflicting damage to the gun.”

Another reason this slug gun is a soft shooter is because of the Inflex recoil pad. “This pad is not your run-of-the-mill pad,” Grange said as he explained how its internal geometry directs recoil down and away from your face. You can actually see the geometry he’s talking about inside the pad and understand how it works if you take it off to add or remove stock spacer shims when adjusting the length of pull.

A series of stock shims make it possible for the user to adjust length of pull. Special geometry inside the Inflex recoil pad (below) directs the recoil down and away from your face.
A series of stock shims make it possible for the user to adjust length of pull. Special geometry inside the Inflex recoil pad (below) directs the recoil down and away from your face.

Other SX4 features include a larger and reversible safety, larger operating handle and a larger trigger guard, which enables late-season hunters to shoot with thick gloves.

SX4 controls are oversized, making them easier to use when wearing gloves.
SX4 controls are oversized, making them easier to use when wearing gloves.

Range Testing the SX4

To see if the Winchester Super X 4 Cantilever Buck stood up all Grange said it was, I topped it with a Riton RT-S MOD5 3-9X40mm scope and took several boxes of Winchester Deer Season and Browning BXS slugs to the range.

Those two loads couldn’t be more different. The Winchester load is more like a conventional all-lead Brenneke-style slug, except it has a plastic plug in its base that Winchester calls a stabilizer. Winchester says it will stabilize in either a smoothbore or a rifled barrel. With a muzzle velocity of 1,600 fps, this 1 1⁄8-ounce slug will wake you up in the morning when you touch one off. The Browning load also leaves the muzzle at 1,600 fps, but it’s a saboted, 1-ounce, all copper, flat-base bullet with pointed polymer tip and stabilizes only in a rifled bore.

The best three-shot groups at 100 yards with both loads were right at 1.4 inches. The Winchester averaged 2.19 inches for five, three-shot groups; the Browning averaged 2.10. That small of a spread between two so very different loads is pretty darn impressive in my opinion.

I also brought a random mixture of leftover slugs from past range sessions to see how the Super X4 Cantilever Buck did feeding a variety of slug types, and to break in the gun a little before firing the Winchester and Browning slugs for accuracy. The first shot was with a Rio Royal Brenneke — a 1 1⁄8-ounce slug at 1,410 fps — and it failed to cycle the gun. It was just that single round — all other leftover Rios worked fine, as did all other types of slugs, so I’ll chalk the malfunction up to it being the first shot ever out of a new gun and not worry about it.

The trigger group is quickly and easily removed for cleaning or maintenance.
The trigger group is quickly and easily removed for cleaning or maintenance.

The only thing I could legitimately gripe about is that the Super X4 is a shotgun, so it has a shotgun trigger. It’s long, heavy and mushy compared to a nice, crisp rifle trigger. That doesn’t help with accurate shooting, but it’s necessary because you can easily switch out the Cantilever’s rifled barrel with a conventional aftermarket smoothbore barrel for bird hunting, and there a typical shotgun trigger is better than a rifle trigger.

The only gripes Grange hears about the Super X4 Cantilever Buck are about its availability. 

“Anytime you introduce a new and exciting product, it is difficult keeping the pipeline full,” he explained. “It usually takes a couple seasons to catch up to demand. Even though that’s a good thing for the manufacturer, it can be frustrating for the consumer.”

Grange says nothing about the Super X4 Cantilever Buck surprises Winchester and that it is everything they knew it would be. “It is of the Super X platform,” he said. “It is a time-tested workhorse. Its performance history cannot be disputed.” 

I won’t dispute it and must agree with him that it’s a “reliable, pleasant to shoot, accurate slug system.” If we had had slug guns like the Super X4 Cantilever Buck when I lived Back East, they would have been gamechangers for sure. Slug guns such as this would have lengthened our effective range, increased our confidence and success rate, and made us overall better in the field.


  • Manufacturer: Winchester Repeating Arms
  • Model: Super X4 Cantilever Buck
  • Calibers: 12-gauge, 2 3/4 and 3 inch
  • Action: Semiautomatic slug gun
  • Magazine capacity: Four 2 3/4-inch shells
  • Barrel: 22 inches fully rifled and chrome plated
  • Trigger: Single-stage non-adjustable
  • Sights: Fully adjustable folding rear, TruGlo fiber-optic front
  • Stock: Black synthetic
  • Overall length: 43 inches
  • Weight: 7 pounds 8 ounces
  • Other: “Drop-Out” trigger assembly, ambidextrous crossbolt safety, length of pull spacers, Inflex recoil pad and sling swivel studs
  • MSRP: $959.99
  • For more information, visit


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