It is not the preferred setup , but it should be doable. It is all about choosing your shot. I have talked to a couple guys who have taken deer with the 357mag.
As far as the guys at the LGS, they are trying to sell guns. That being said, I would prefer a .44 or larger hole to start with.
One day, I shall come back. Yes, I shall come back. Until then, there must be no regrets, no tears, no anxieties. Just go forward in all your beliefs and prove to me that I am not mistaken in mine.