If you want "good" penetration (not just 12-14 inches in test gelatin) and expansion from a two-inch barrel your going to need at least a mild .357 load. (Or .327)

If your willing to give up some penetration or the expansion .38 special can do that with less recoil and blast. (And so can .32 magnum, and you get an extra shot, too)

I've tested many .32's, .38's, and .357's from a snub over my chronograph.