For deer hunting theres no need for anything higher than 12x in my opinion. When hunting, my scope at all times is at 4 or 5. With a higher magnification, you see more movement with yourself. With a 9x, a deer at 100 yards is dead to rights and youre own personal error or steadiness is minimal enough to when you get the crosshairs on the vitals it will hit. If you have a 20x scope zoomed in at 100 yards, its harder to hold steady unless you have a sturdy rest.