What little I (think) I know is that CZ doesn't make a .357 SIG P07/P09. They don't make .357 SIG barrels for the pistols. The 9MM P07 barrel (even if rechambered to .357 SIG) has a different width barrel hood than the .40 S&W barrel so the rechambered barrel would be sloppy in a .40 S&W slide, unless the hood was modified in some manner. A P07 9MM slide would have to be modified to allow a .357 SIG round to fit against the breech face, chamber in the barrel.
And even then, if work was done on a 9MM slide to allow the .357 SIG case to fit/feed/eject, etc. the extractor angle/fit might not be right.
The best fit would seem to be using a .40 S&W gun, with a barrel made for .357 SIG. But I can't find anyone making one.
Not sure what it would cost to have a 9MM barrel rechambered and the barrel hood modified to provide consistent/even fit in the slide.
I'd like to have one, too. That was my idea behind buying that P07 in .40 S&W. Then, however, it turned out to be the most accurate of all the many brands/calibers of polymer framed pistols I own and I will not mess with it. I may buy another one some day, and have it messed with, but not that first one.
