I have hunted mule deer with the .357 and I would suggest stickink with an expanding 158 gn. with the longer barrel you will increase the range at which they will expand well and the wieght is a big help in penetration.
Bear in mind that I have put a 150 gn .308 through, in and out, a blacktail at 25 yds, 0 expansion and the energy went into a hillside, but the deer dropped in it's tracks. It was all about placement.
Practice untill you can keep every shot on a paper plate at 75 yds from a field position and then try to limit yourself to 50 yds for real.