while99 - Hmmm, interesting comparison here. The 9x23 is really a rimless 38 Super in a long (23mm) 9mm case that takes a 124 gn bullet at 1425'/sec, the same level we used to load our 38 Supers to and the same level as the original 38 Super loadings. The 38 Super and 9x23 run interchangeably in all the 38 Supers I have shot recently and a lot of 38 Super shooters use the rimless 9x23 brass for their loads. There are a number of handguns chambered for this round (38 Super/9x23) most notably the 1911 platform and I believe Sig also chambers one of their models in the 38 Super as does Tangfolio, I believe. You will find more pistols chambered for the 38 Super than the 9x23, I'm sure.
The 9x23 ballistics are the equal to the 357 magnums famed one-shot fight stopper with a 125 gn bullet at 1425'/sec. The 357 Sig also mirrors those ballistics but has the added reliability benefit of being a bottlenecked cartridge that may feed hollowpoints and flatpoints more reliably. The 9x23 and the 357 Sig are ballistic equals.
The 9mm magnum is about 25mm long and needs its own platform to function a semi auto reliably. About the longest case the 1911 platform can handle reliably is 23mm. After that you really have to deep seat your bullets and that costs you ballistically. Paris Theodore, late of Seventrees Holsters, found that out when he reworked and chambered a S&W Model 39 for the 38 Super. He had to deep seat the bullets to get reliable functioning and the loads were no better than the 9mms. I don't know if anyone still makes a handgun chambered for the 9mm Magnum, but there must be. If I recall, the last one I saw was a pretty hefty package, a Wildey maybe?
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The 356TSW is a bit of a specialty cartridge and I would prefer and recommend a caliber with 'on the shelf availablity'. That leaves you with the 38 Super/9x23 as the most likely candidate for availability, the 357 Sig next. I doubt you will find the 9mm magnum or the 356TSW on most anybody's shelves.
Since your intent is self defense and concealed carry my recommendation would be for the 38 Super/9x23 in a 1911 lightweight Commander sized package or the same in the Sig line, but based only on the probable availability of 357 Sig ammo. Otherwise I will definately recommend one of the Sig line of pistols in the 357 Sig caliber. I am a big fan of bottlenecked cartridges and the 357 Sig is right there. Dang, now ya got me thinkin' I might need a new gun............. HTH. Mikey.