And the 357 sig beats the 9mm out of a 16" barrel by no small margin. Somebody will build a pcc in 357 sig and sale a lot of them.The point of the .357 sig was to get .357 Magnum Ballistics from a auto-loading pistol, right?
If you have had a look at 9mm Ballistics from a 16" barrel, you may notice that a 9mm already attains the muzzle energy of a .357 Magnum.
Ballistic by the Inch
I don't think I'd be running hot reloads through the 40 sub. If the plain vanilla 357 sig factory loads are beyond its capabilities those hot 40s might tear her up in short orderA .40 s2k can really make some serious power so try it if a 9mm isn't enough. It can push a 155gr bullet to 1600fps with longshot powder. A 135gr can probably go 200-300fps faster. Better go with a heavy bolt and sumo handle first though.