Here's the description from Winchester's web site.
I like 3" guns and with the variety of shotshells loaded today, I see little need for the 3.5" ones. I've also found that 3" guns generally pattern better than 3.5" guns and they certainly kick less.
I wanted to put this gun through the paces in every shooting and hunting situation. Over the last 11 months, I've done that.
I've shot sporting clays, trap, skeet and 5 stand. I've also hunted doves, quail, pheasants, ducks, geese and turkeys.
I've exposed it to the varied weather conditions of the last 11 months, ranging from very hot and humid to very cold and dry. On several occasions, both the gun and I were thoroughly drenched with rain. I did not "baby" it in any way. I cleaned it thoroughly before shooting it for the first time and whenever it was soaked with rain, otherwise, I just shot it.
I really liked the way the gun felt in my hand the first time I picked it up and shouldered it. It's very light and comes naturally to the shoulder. It balances well in the hand and is easy to carry at the range or in the woods.
I've watched Patrick Flanigan shoot one of these guns many times and am always amazed at the number of accurate shots he can get off in just a few seconds. While I certainly can't do what he does, I can testify that the gun is very fast. If you don't get off 3 shots, it's not the fault of the gun!
I shot a lot of Winchester AA shells, both trap, skeet and sporting loads. With those shells the recoil is very light and the Pachmayr pad is really all that you need. Turkey loads are a different matter however.
I used the SX3 to test a number of different turkey loads. All were 3" full power loads and all pack a real punch. The slim lines of the SX3 that make it so easy to shoulder are not a real advantage when you're shooting 3" turkey loads from the bench. Leaning into those shells, I could feel a real kick.
I tried both a Shooter's Friend recoil pad and an Evo Shield recoil shirt in my tests. Either of those tamed the recoil of the SX3 and that combination reduced it to a gently shove. If you're planning to shoot 20 or 30 different 3" turkey loads, I'd recommend one or both of those to lessen the felt recoil.
In a hunting situation, I never once felt the recoil and never had a bruise or sore shoulder.
How did the gun hold up? I had no malfunctions throughout my tests. Any complaints? I'd like a center bead added to the ventilated rib. That's not a big item but it's kind of expected on a gun in this price range and of this quality.
The SX3 is an excellent gun, very reliable, easy to shoulder and dead on accurate. POA/POI was "right there" straight out of the box, for me. There are shims that allow you to adjust the fit, if that's not the case for you.
I really like the appearance of the gun. The gray finish looks great and held up well under some pretty severe conditions.
If you're looking for a light, self-loading 12 gauge shotgun that's very quick and that you don't have to baby, I'd recommend that you consider the SX3. It's a proven design and in all my tests, lived up to the reputation set by the Super X and the Super X2.