I have a mossberg 500 20 guage with the field barrel. I think a shotgun is the best weapon for home defense but its hard manuvering through the house with the long field barrel. Also I'm not sure if the 20 guage is enough weapon. So should I buy a 18.5 inch 20 gauge barrel for my current gun or should I go out and buy a 12 gauge tactical model with 18.5 inch barrel?