Most guys seem to just "sight in" their rifles and don't practice shooting at different ranges. So when a predator comes it at anything other than "that" range, they miss. Practice, practice, practice. Shoot at all kinds of different ranges, including unknown ranges. You also have to make sure that your scope on your rifle matches your stand set up. I have taken plenty of predators with a shotgun but there is no reason that a rifle cannot be used at close range.
Regardless of whether you use a rifle or shotgun, practice makes perfect.
Regardless of whether you use a rifle or shotgun, practice makes perfect.