That is correct. I should've added that .40SW shouldn't be fired through an auto pistol chambered for 10mm as a matter of practice, but in an emergency (and only an emergency) I've heard that it can be done (but I never have). It is never smart to use ammo that is different from what the pistol is chambered for. The S&W 610 revolver is different as it uses full or half moon clips and "headspaces" on the rim.
(PS, I just wish I got to shoot enough to answer some of these questions myself, drat it!!!)
I never get to shoot enough.
You and me both.
I got out my digital caliper and measured the case dimensions of the 10mm and the .40 S&W.
The 10mm measured .424 at the case head and .421 at the mouth. The .40 S&W measured .421 at the head and .420 at the mouth. That is darn near a straight walled case and I am surprised they feed as well as they do.
It did strike me that the .40 S&W (Both cases were R-P) is slightly smaller and would likely slide down the chamber a little. The extractor would probably keep it from going far but it really does sound dangerous. In fact really dangerous.
Like you, I might try it in a real emergency but nothing short of that.