OP, I assure you that a 4" smith with 180gr JSP's or 180gr HC or 200gr HC bullets all work well, and kill deer in 357mag. One of mine is a 4" Smith 686.
Go have a good time and shoot straight. Dang, they even work great out of the 3" Ruger SP101 with 180 HC bullets. (my hand loads).
Edited because of lead weight typo's...