No one said 56mm is too big.........any larger is not helpful.Objective diameter / magnification = exit pupil. A larger exit pupil is easier to "find" when you get behind the scope, even if the exit pupil is larger than your actual pupil. In terms of "brightness", larger exit pupils are brighter, at least until the exit pupil exceeds your actual pupil diameter. For reference, in daylight, your actual pupil is 2-4mm, and 56mm/24X = 2.33mm exit pupil, so I'd argue 56mm isn't "too big" by any stretch. It might be too heavy, too bulky, too expensive, or too high over the bore, but life is about trade-offs.