This is a good thread. I have a S&W 60-18 (5-shot J-Frame 357 with 5" barrel). I want to find a moderate load that is not also just a 38 Special +P load.
The problem is good data is hard to find.
Much of the data out there seems to use the 40,000 PSI SAMMI guideline form pre-'95. Vitavouri seems to use CIP which is something like 43,000 PSI (by another method). Still, above where I want to be. Lyman seems to go by a ~40,000 CUP max, which isl well over 35,000 PSI.
I want to be something like 32-35000 PSI with a slow-to-mid range powder that will actually burn up in 5."
But what everyone seems to offer are either cat-sneeze Bullsye/Unique/Universal/Tightgroup 38 loads or they want to give you basically a starting load with the slow magnum powders, almost all of which are inefficient. 2400/296/AA#9 all need to be pretty close to that 40K mark in order to burn well it seems. I've tried magnum primers. It helps, and AA#9 is the best of this group, but I think they are not very efficient, even with 158-168 grain bullets.
Blue Dot seems promising. But I dislike blue dot with those big flakes. It also doesn't approach case fill. The limited testing I have done clocked ~1100 FPS. Hardly any more than 38+P
Two powders that seem to make sense to me are AA#7, Vit 3n37, and Shooters World Heavy Pistol maybe? At least Alliant and Shootersworld have data with 357 Magnum at the 35,000 MAX. Unfortunately, vitavouri doesn't seem to publish starting load pressures, which could possibly be a good.