Am I under-gunned without a 12ga for home defense?
No.
The shotgun (and the rifle) are greatly over-rated for home defense in my humble opinion.
I have great respect for a shotgun, but a pistol is something that you can have on your side at all times, and everywhere you go.
Say you're watching TV late one night, the shotgun is close by, the wife and kids are sleeping...
Okay, commercial break, and nature calls....so what do you do?
Well, you get up and go to the bathroom just like anyone would.
I'm betting that you don't take the shotgun with you to the bathroom for every little potty break.
Now you're done and just as you're washing your hands, you hear the sound of breaking glass....
You would probably be wishing that you had a pistol on your side right about then.
Let's say you're in your home checking out The High Road on your computer, and it's about 9:00pm, when suddenly you remember that you didn't turn off the sprinkler (you were watering the garden or lawn, whatever)....
Of course you're just going to run out and turn the water off, and it will only take a minute or two, so you don't take the shotgun with you....
Just as you turning the water off you catch some movement out of the corner of your eye....
You turn and see three guys in your backyard, positioning themselves between you and the entrance to your home.
You would probably be wishing that you had a pistol on your side right about then.
Let's say you're in your garage tinkering with the lawn mower.
It's 95 degrees out and so the garage door is open to let the heat out.
Suddenly two guys walk right in to the garage, and one has a baseball bat....
Now, do you have your shotgun with you every time you go and work in the garage?
I'm betting the answer is "no".
But you could certainly have a handgun on your side.
Anyway, I think you get the point....
You can never tell when you might need a weapon, and a pistol is something that you can have on your side nearly all the time, and nearly everywhere you go.
Yeah, rifles and shotguns definitely are more effective than handguns.
And yeah, if you live in a God forsaken post-apocalyptic "Road Warrior" type of setting, then a rifle or shotgun might make sense.
But realistically, in today's rural, urban, and suburban setting, the rifle or shotgun is just not something that you're likely to have with you when you really need it.
So my advice is to use that money on getting another handgun.