I'd use a powder more suitable for 357 mag. I suggest Win. 296 over the likes of 231 (too fast). You'll get 350 more fps with less pressure. Use a magnum primer with a heavy bullet crimp (high bullet pull). Head the warning about not reducing powder charges for 296. Here's the web site where you can down load Winchester's reloader manual 15.
http://www.winchester.com/ammunition...components.eye