I've used the following load successfully through my Marlin .357 (18.5" barrel, microgroove)
GM 148gr DEWCBB, Fed 100 (or Rem 1.5 or CCI 500) primer, 3.3gr N320, C.O.L.: 1.382".
925fps, 281ft-lb. S.D.: 13.5, CoV: 1.2%
Group size (edge-to-edge, 10 shots): 34mm.

NB. This load was no use in my Taurus LBR; there I got around 710fps, and a group size over 70mm...