I've killed several deer with my 6'' 686. All were within 40 yards. Don't know if I would shoot at one if it was much farther than that. I look at the .357 for deer as very similar as to hunting with a bow. Both in yardage limitations and shot placement. Penetration is key with the .357, Cast or JSPs 158gr or 180s. If you're shooting factory, any name brand ammo should work. Federal American Eagle JSPs work well as do the Federal Fusions. Remington's JSPs shoot and work well also. Iron sights work well out to feasible yardages, but if you must use optics, make sure that the scope does not interfere with your ability to cock the hammer in S.A. Red Dots work well on 686s.