The 28 is a great gauge...just less 'margin of error' than with the 12. It's going to throw less shot, of course, but at approx. the same velocity. If you're a good enough wingshooter, then yes...you can hold your own with the 28. An obvious drawback is the smaller variety of factory loads when compared to the 12 or 20, and correspondingly higher prices. But just remind your Dad it's more of an expert's gun, and if he does well with it, what does that say?