Use .38 Spl loads and have at it. If you start way low, just make sure the bullets exit every time. If you don't want to worry about that, then use mid-range .38 Spl loads and up.
I have tried many light loads in .357 brass. Some medium speed powders don't do so well because they are fairly position sensitive and/or don't burn well in big cases at low pressure levels, but almost any fast powder will be OK. The slow powders shouldn't be used at all for this.
I have shot a lot of X-Treme 158 Gr SWCs at around 800 FPS in .357 brass. Very low recoil/blast, accurate, and fun. It is the bullet I have settled on for this application. Most any 158 Gr lead bullet will work great as well.
I have tried many light loads in .357 brass. Some medium speed powders don't do so well because they are fairly position sensitive and/or don't burn well in big cases at low pressure levels, but almost any fast powder will be OK. The slow powders shouldn't be used at all for this.
I have shot a lot of X-Treme 158 Gr SWCs at around 800 FPS in .357 brass. Very low recoil/blast, accurate, and fun. It is the bullet I have settled on for this application. Most any 158 Gr lead bullet will work great as well.