jcwit, it isn't real hard to find out! Google "38 Super Auto pressures" or just pull up the SAAMI websight. Todays 38, super ammo is loaded to about 35,000 PSI, which is the same as the 9X19, or Luger, or Parabellum, or whatever you want to call it.
I have talked to the people at Black Hills and:
on the record: We cannot condone shooting 38 Super ammo in any gun not specifically designed and chambered for that specific cartridge, and so marked on the barrel.
Off the record: Our 38 Super ammo is loaded to the same pressure as 9mm ammo. The only reason it gets slightly more velocity is the larger case capacity, BUT IT IS LOADED TO THE SAME PRESSURES.
And those pressures are well within the safety margins designed into the pistol.