Mossberg used to make a Camper PGO pump in .410 gauge and that would make a handy little weapon for HD use at close range .
It's a gauge that is manageable and at close range, very effective.
I agree that walking to a perp instead of letting a perp walk to you spells death since you are on PERPs terms when you do that.
But, tactics aside, I would familiarize myself with my shoulder stocked short barrelled shotgun first.
I don't believe I've ever seen any troops in "Nam, the Gulf War, Iraq, or Afghanastan use PG shotguns and for very good reason.
All of the trench guns I've seen, past, present and future, are designed with full stocks.
All Hollywood guns are back@$$wards of reality and debunking myth seems to be the biggest hurdle when dealing with folks new to firearms.
I have an old Stevens "Westpoint 167H" that was cut down to 20" and retains the full stock.
I got it from a friend who goes up to the mountains to see his folks and he brought the Stevens home and I traded a single barrel for it .
I cleaned it up, installed new springs, reblued and deburred all sharp edges and shot it to make sure it would work and am happy with it as a home defense shotgun.
I have two other shotguns and would not hesitate to use them in a pinch, but the ol' Stevens is solid and feels god to my shoulder.