Zeke, you did an exceptional job of stating the facts of the .357 Sig round. You were also dead-on in the velocities. I just wanted to expand a bit on your post.
The reason Sig and Federal were so adamant about this rounds' creation was the overwhelming success of the .357 Magnum round in real-world shootings
. While companies like Coonan Arms believed that a firearm could be built around the already-existing cartridge, Sig wanted a cartridge with the exact same terminal ballistics that could take advantage of a semi-automatic platform and all of its benefits, such as double-stacked magazines.
Much analysis and work yielded exactly that in the .357 Sig. A 10-year study of real-world shootings including both the .357 Mag and .357 Sig have proven that the rounds are so close to being the same in terminal ballistics that their results are indiscernible from each other. The bullet used is the exact same in both rounds and the shouldered round feeds very reliably in the semi-auto platform.
This round is not similar to 9mm, .40 or 10mm in its design or performance. It is a proven fight-stopper just as its battle worn progenitor has proven to be. To equate it to any other round is to do it a disservice and cheat yourself out of what may be the best self-defense caliber for a semi-auto as proven in actual shootings.