you had made mention that it will be sitting on a semi target rifle. what are your plans for this? if you want tight groups or pshoot for small targets id maybe opt for something with some power. but if you just want to ring gongs all day then a 3-9 will be just fine. personally id go for something in 4-12 or ideally 4-16 to really help make use of all the potential a 6.5 creedmore has to offer without having to much magnification for most deer hunting. if you can ever get the chance to compare a 4-16 against something even as big as 6-24 you will see there isn't much difference out to 800 yards or more if gongs (or anything else with a 10'' vital) are your planned targets.