I have a mossberg 835 12 guage and I do hunt turkeys with 31/2 inch 5's and with the exception of checking my pattern every year I don't want to shoot the shotgun unless I am shooting at a Tom.It flat out pounds you.I have owned a .300 win mag in a winchester feather weight.Light gun big caliber,it didn't kick nearly as bad.
A decent solution is to get a shotgun that is a semi-automatic,because of the release of gases with the ejection of the shell the recoil is significantly less.A high end recoil pad is a pretty good idea too.