Re: What magnification needed?
I have a 3.5X10 Leo on a 240 Wby and it is a fine scope for whitetail deer for 50 - 500yd and particularly when most likely the shot will be at about 100yds. I keep it set on 3.5 and dial up if there is a need.
Optics are good early in the morning at first light on low power.
If I was to engage in target shooting to 700 yds I would probably want more magnification but life is a compromise.
The Smokin Fur Rifle Club