I have to agree with the .44magnum crowd.

While a 180gr BB from a .357 contender is no slouch I think that it is riiiiiiiight at that marginal level and does not really give you a whole lot of lattitude for a less than perfect shot.

A medium loaded .44mag out of a contender would be a much better choice.

Just for the sake of comparison, looking at the Taylor KO number for these two rounds:

180gr .357 @ 1800fps = TKO 16
280gr .44 @ 1250fps = TKO 21

That is a 31% increase if you subscribe to the TKO as an indicator of killing power.