magnification on an AO scope is a tool to be used to aid you in shooting.

it does more than just make your target appear larger. think of it like the aperture of a camera. you're influencing the amount and intensity of light entering your eye.

in low light, which is where i get a considerable amount of my shot opportunities, you can adjust your scope to give you a better advantage in the low light, but always at a compromise.

the higher magnification you go to, usually, the less light gathering you have in the scope. so, if you're scope goes to a million power, it'll do you no good 20 minutes after sunset, for example.

3-9x40 has been a go-to model for a long time. recently, with the increase in quality and performance of scopes, lots of people are getting 3-12x50's or 4.5-14x44's which offer somewhat of an edge over older models.

i have a 4.5-14 nikon on my winchester 243. i use it for coyotes often, i use it for deer, i use it for anything that i can use it for legally. (even an american bison)

try several, consider the scopes weight on the rifle and how it will affect its balance, which will make a difference in how you shoot it in the field when you're not on a bench at the range.

if you have a good gun shop, take it in there and see if they'll indulge you and mount a couple for you to try and see how it looks and feels.

a couple years ago, i read an article about how to set up a new rifle for maximum performance. i wish i would have saved it for you, that guy knew his stuff. he detailed the importance of knowing the load you're shooting and sighting in your scope for your rifle's maximum point blank range. read up on it. it will help.