preventec47: it really isn't going to matter what weight bullet you use if you are staying within 357 magnum pressure ranges. The 357 magnum is, after all, by design a P+ cartridge with pressures up to 42,500 cup. The Winchester factory load for their 110 gn jhp is a 42,500 cup pressure load. Their 158 gn loads range from 38,000 - 42,500 in pressure, powder dependent. Of interesting note is that their 200 gn load using 296 powder is rated at only 35,000 cup. By comparison, the 38 Spl runs at 11,000 - 15,500 cup pressures with the P+ ratings running to 19,000; quite a bit of difference between those ranges and the 357, don'tcha think............
Also, those lightweight 380 bullets are designed for use in 1:16 twist barrels and while they can also be used in the 38 Super their accuracy might suffer in a 1:18.5" twist of the 357. Maybe not. Years ago I loaded some 9mm 125 gn rnsp into some 38 Spl cases over the heaviest charge of 2400 I could find for a bullet 25 gns heavier and from a Colt Detective Spl and two different Pythons the accuracy was pretty good.
I would consider a lower pressure 357/38 Spl load with a heavy bullet rather than the other way around. The idea of having +P cabability is comforting only in that you know the revolver is capable of handling +P loads without failing but you don't get someting for nothing and with increased pressures you get increased recoil. jmtcw.