You should all do an experiment.
Dial your scope up it's highest magnification and shoot a group at 200 yards. Now dial it to it's lowest magnification and shoot another.
Shoot these groups from a field position, NOT from a bench rest!
You may be surprised to see that the low magnification group will be the smaller of the two - or, there will be no difference at all.
What does that mean? To me, it means that the high setting magnifies any "shake" which is always present when shooting offhand. You are also narrowing your field of view (and slowing down target acquistion) at a time when real speed may be important.
Now, if your groups are smaller with low magnification at the range, consider what will happen in the field when that big buck adrenaline rush hits you and you get a real shake going...
Even if you're shooting from a stand, the deer never show up where you expect them and you'll find yourself shooting from an awkward position with a magnified shake.
This is one of those things you have to try for yourself to believe, so check it out next time you go to the range. High magnification might look good from a bench rest, but in the field it's a handicap.
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Keith
The Bears and Bear Maulings Page:
members.xoom.com/keithrogan