Not trying to hijack the thread, but I have a question that is (kind of) relavent, as I've been considering the same. I'm just waiting on finding primers before getting started.
I understand the whole capacity, powder charge, pressure situation. I.E. too much unused space (reduced loads with fast powder) can produce an increased "spike" in pressure.
The question is this...Can you do, as the OP asked, and load a .357 with a .38 charge, but instead of loading to an OAL of the .357, seat the bullet that little bit deeper and have an OAL equal to a .38 Spec? Will this make pressures unsafe? I really don't see why, but I'm just learning here also, and wanted to ask the experts.
I've been considering doing this for practice loads only, but carrying full mag loads. I just want to maximize my trigger time with my new carry revo.
Sorry again if this is considered hijacking, but again, I see it as a relevant question to add to the OP's question.
Wyman