Just stumbled onto this thread. I have a 5" .356 TSW that I purchased new back in the early '90s for IPSC competition but moved to California for work and stopped competing. Haven't fired it much over the years to save the brass, though I hear some manufacturers have started making it again...
I have a 356 TSW pistol from the S&W performance center. Very nice gun.
Did a lot of reloading for it back in the day when I was actively using the gun in IPSC in the early 90's.
My recollection is that the cartrage wall thickness was the same or very nearly so to that of the standard 9x19...
I have a .356 TSW that I purchased back in the early 90s for use in IPSC competition. I also purchased 1000 rounds of 147 gr TMJ ammo and a couple hundred HP rounds too.
Also bought reloading dies and saved what brass I could and worked up reloads for gun.
Moved to CA 15 years ago and stopped...