I agree, Steve - slugs don't kick as much as heavy shot loads. A 1-1/2ounce 2-3/4" mag lead shot load was 656.3gr. weight. This is 75 to 100gr. heavier than the heaviest slugs avaialable. I think there were some 575gr. Brenneke's at one time(maybe still available somewhere), but see they've reduced the weight.
; If you want recoil, use heavy black powder loads. They will make you think you're shooting something powerful- and you are.