I see the 9x23 as a useful step between 9mmP and 10mm, and I actually bought a 1911 chambered in 9mmP just to convert it to 9x23, but someone wanted that gun more than I did, so the project never really went anywhere.
357 SIG appears to have come a ways from its one-trick-pony origins, but I'd prefer 9mm capacity with my 9mm bullets (while acknowledging a single stack anything doesn't hold a lot of bullets).
9x23 is a tapered, rimless round like 9mmP, not a straight-walled, semi-rimmed round like .38 Super, so I'd say 9x23 was intended to improve upon Super, but the only similarities are length and the bullet itself.
357 SIG appears to have come a ways from its one-trick-pony origins, but I'd prefer 9mm capacity with my 9mm bullets (while acknowledging a single stack anything doesn't hold a lot of bullets).
But the 9x23 derived from the 38 Super and not the 9mm.
9x23 is a tapered, rimless round like 9mmP, not a straight-walled, semi-rimmed round like .38 Super, so I'd say 9x23 was intended to improve upon Super, but the only similarities are length and the bullet itself.