Thanks for all the advice. Sounds like Bullseye will be the way to go for the target loads, still have to decide about the full-house loads. Can you get full house loads without a lot of muzzle flash, or is that just the nature of the beast, as it were? Sorry if I sound like a noob, I've been hand loading for many years for about a half-dozen calibers, but this is my first magnum handgun cartridge.
Bill, I knew those powders could be used in the .357, I did my initial research to see what powders I had that could be used before I posted. I've got Lyman #48, among others, and will be using them when it comes time to work up the loads. When I found out I had 10 different powders that would work, I just wanted to get advice from those who've been there about the powder to start with.
As to keeping the speed down with the cast bullets, how low should I keep them?
Siskiyou, +1 on keeping the loads matched to the cases in the .38s. I already do that so there is less chance of mixups.
Unless it was recommended by a lot of people, I was planning on staying away from 296 because of some of what I've read - make sure to use heavy crimps, be sure to use magnum primers, don't reduce loads, and so on. Unless there is a good reason to use it, I'm thinking I'll save it for something else... :-)
Just a Shooter