Never mind varmints at long range, I'm thinking of deer, on that .280 I'm slowly stalking. Maybe a pig. If you want to make sure you can make a shot very early or very late, on an overcast day when the light's low (and very blue), do you want a large objective? Never mind magnification, this is a different question. I suspect that low light level, rather then great magnification, is the best reason for an objective of 40mm and up. BUT, I've never hunted. So what do you think? What properties do you want, in the scope on the rifle in your hand, when a large buck appears in your binoculars at 200 yards in the last minute of legal hunting hours on an overcast day?