Whatever the sight-in range, checking the bullet impact in relation to the cross-hairs at all ranges from 10 yards to 50 yards is a good idea. Scope height can screw things up at close range as the bullet is starting 1 1/2" or more below the line of sight and with a 100 yard zero and may not be up to the crosshairs until past 50 yards - depending on rifle, scope and load.

In getting ready for dangerous game hunting, practise fast shouldering,shooting, reloading and shooting again at close range. This is a good idea - never wasted ammo. The biggest problem I've seen with big game hunters is they don't practise enough at home - if at all. Only a few are familiar with their rifles. Only the very rare one is fast at shouldering his rifle - it all comes down to familiarity. Can't find it in the scope is the most common thing I've heard. If you can see it with your eyes, it MUST be in the scope. Practise is the only thing that helps here. Shooting single shot off a bench at 100 yard paper target is not practise.