How much magnification?

[user2026]

To address the confusion, I am not using my rifle scope like binoculars. Not sure why so many think that. I hunt on a dairy farm and the only places I can see 400 yards are in wide open fields. In the same wide open fields, at 400+ yards, I can tell without any optic that a deer is a deer. If I see a flicker of movement on the edge of a field, I use my 7x rangefinder to see if its a deer or person or lost dog etc. Once I know I'm looking at a deer, I just want to throw the rifle on it, with the safety on of course, and id what the deer is. Anytime I'm looking at a deer at 400 yards, I'm already steady, and just want enough magnification to see if there are 3" spikes, or nothing on the deers head. Just want to know how much magnification I need for that.