w231 is a good medium velosity powder for the 357 mag while the 296 is a 97% to full house powder that many like.

2400 will do target and top magnum velositys with regular primers..............

I have also had good results with Universal clays,Unique,Sr4756 and BlueDot with the heavier JHP bullets in the 357 mag.but can "Peak" near the top velositys.
imr 4227 did not work well in my test with regular or magmum primers but thats in my 6" 686................