This made me choke on my coffee...
A perfect OB response.
I certainly talk a lot and stuff. No denying it.
Any shotgun is going to perform like a giant rifle at super-close range (like inside your house). I'd think that birdshot would almost be like a slug at such close range.
A shotgun will perform well with #7 or #8 at close range. The problem is, the perp may not be 5 inches from the tip of your barrel.
The problem with birdshot for HD is that you're depending on the person's PERCEPTION of pain to stop him/her. If you want to do REAL damage, you need something that will penetrate more than 5 inches.
It all goes back to design. What is birdshot designed to do? It's designed to penetrate minimally and knock small birds out of the air.
What is buckshot designed to do? Penetrate well and knock down a deer, which is a mammal. And oh yea, people are mammals too.
Here is my take on a shotgun for home defense. I do not advocate birdshot. Birdshot for HD
And here is TNoutdoors9's test. He also thinks birdshot is not good for HD. TNoutdoors9 Birdshot
5.56 with frangible rounds sounds safer to me. Maybe something like Barnes Varmint Grenades?
I completely agree with this though. One small perjectile traveling at over 3000fps is more than enough. And with a frangible/fragmenting round, you have much less chance of hurting someone/something you don't intend to shoot.
Here are a couple of videos from TNoutdoors9. He tests the Mil-spec open-tipped 5.56 rounds and the Hornady Vmax in 223. Both perform very well in penetrating enough and transferring ALL the energy from the shot into the TARGET, which is where it should be. TNoutdoors 5.56 match TNoutdoors Vmax