I'd agree that a high-power magnum rifle with a partition or bonded core bullet would be the first choice, if it came to defending yourself from imminent charge. However, if you have a target running at you and your rifle is scoped, within 50 yards, the rifle would become much more difficult to get off an aimed shot than a magnum revolver of .44 or more powerful.
Let's hope we never have to use either for that purpose.