Like Dand said,
Unique in my opinion is very hard to beat for moderate 357 magnum loads is bullet weights from 125g to 158g. Higher velocities can definitely be obtained with powders like 296, H-110, AA-9, and especially Lil' Gun, but honestly, out of that short barrel, I doubt the gains would even be noticeable in the real world of shooting.
A good 140g HP like the XTP-HP's, or Remington 140g SJHP's pushed by a decent load of Unique, and ignited by CCI-550 primers should give you all the performance you'll care to handle in that gun.