What about a semi auto gas operated 12 gauge? They will kick less than a pump or single shot. Granted, they still kick fairly hard with buckshot. I've shot some 20 gauges that are just as bad or worse due to them being lighter and on a smaller frame. I think a semi auto 12 gauge is what I'd go with, but if not, I'd get a 20 gauge and order some buckshot online. No way I'd give her a .22 for home defense.