A .357 Magnum usually is not a legal method of take for big game in Colorado. It takes a very long barrel and pretty hot loads to make the legal requirements. Last time I looked only Corbon loaded the .357 Magnum with published ballistics in an 8" bbl that were legal.

I still think its silly to carry a sidearm when rifle hunting. It takes a bunch of mental contortions to create a scenario where a holstered pistol is "faster" to engage a hostile bear or lion than a rifle you've got in hand.