If you are going to only shoot at 50 yards, then a shot gun scope may work for you. They are focused in at 50 yards, usually no adjustment for any thing else, but will work out to longer distances if you keep your eye centered in the lens. They some times have more eye relief too (some where around 5"). I think this is especially applicable for a heavy recoiling gun. You will not need a high powered scope for this duty a 4X would be plenty, I have a straight 2 1/2X on a 44 Mag for this same kind of work. If you want a variable, then get it 2.5 X 5 or 2 X 7 some thing on that order. They usually have a bigger field of view than a rifle scope, because they are made for work up close. They are usually ruggedly built and will take recoil very well. Your dad has given you good advice, buy the best scope you can afford, you will not be sorry. I have replaced several scopes in recent years with better quality ones. A good quality red dot might also work for you. Good Luck and Good Shooting.