Putting aside that you ignored the question that was asked, I'll respectfully disagree with your statement (except for the round count.

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The Shield is ~50% heavier than a 340 and is only 0.2" shorter. You can't stage the trigger, felt recoil is relative to the shooter, and a lighter 9mm bullet shot out of a 4" barrel will still be moving slower than a heavier .357 shot from a 2-2.5" barrel.
Of course, YMMV.......
I'm sorry my post was unclear. The reference to "shorter" was meant to be an additional description of the Shield trigger, not a reference to the overall length of the Shield.
I should have said "the Shield has a trigger pull that is lighter in weight and shorter in its length of travel than the revolver."
That said, I was not ignoring the original question, but trying to get the OP to think outside of the box in which the original question was framed.
I am old, and I grew up on revolvers. I love revolvers, and would never feel that one is not well-armed with a revolver for most applications.
That said, I relegated the revolver to range fun back in the 1970s after I found out, first hand, that although semi-autos occasionally "jam," when a revolver does so, it is often not a quick fix. I won't go into the details, but suffice it to say that I discovered that a Colt Lightweight Commander concealed easier than a J or K frame and the increased capacity, lighter, crisper trigger, better grip, and most importantly, the better cartridge all make for a better concealed carry choice. It is surprising how close a typical carry revolver, such as a Model 19 snub or even a J frame, is in size to a Glock 19 or 23 or a Colt Commander. Just lay one on top of the other and look at the amount of real estate each takes up. Then look at them from the back and see which one is wider.
To each his own, but I do not find a J frame .357 with a steel frame any easier to carry (it certainly is not a pocket pistol) due to weight, and I do not find an AirLight .357 pleasant to shoot enough to really become competent, especially when considering fast follow-up shots, the possibility of more than one attacker, etc. I will grant you that the Airweight 38s or AirLight .357s are easy to carry, but I counter by saying that any J frame is harder to shoot well and in today's market, good ammo for the 38 or .357 is more expensive than good ammo for a 9mm or .40 auto, at least in my area.
Now, setting all of that aside, if I had to answer the question as to the best carry .357, my choice is the 3 inch K frame, such as the Model 13 or 65.
I hope that clarifies why I answered the way I did.