I don't think that's accurate. There is a difference between .357 and 9mm even though they are both .355. (keep in mind I am no reloader)
Sorry I was mixing info. Here is what I had read.
"The .357 SIG offers nothing comparable to reloaders. In fact, it is a somewhat unusual pistol cartridge to reload. Brass is available, but not particularly plentiful. Care must be taken during the resizing operation due to its bottleneck case form. Bullets may not be roll crimped because the case headspaces on the case mouth instead of the shoulder or rim. .40 S&W brass should not be reformed into .357 SIG brass; the resulting cases are too short to maintain proper headspace. Bullet diameter is the same as other 9mm pistol cartridges, but not all 9mm bullets are suitable for use in the .357 SIG. In particular, the NATO style 9x19 FMJ bullets may not be used. Their taper is such that not enough bearing surface contacts the short neck of the .357 SIG case. That is why Speer makes special 125 and 147 grain bullets specifically for the .357 SIG. As with any semi-automatic pistol cartridge, reloads must not vary far from factory load velocities or the gun may jam. And autoloading pistols throw their brass all over the place, making recovery difficult and time consuming."