The longest shot inside my home is 29 feet. There is no one living here except me and the wife. I have 1/2 dozen Mossberg 500's and Winchester 870's, all bought from farm estate sales over the years. Each one of them has been modified to a 18.5 inch barrel and are hidden, scattered, over the house so I can get to one immediately if not sooner. I decided one day after reading one of the many threads about home defense with a shotgun, I would take all of them to the range that I run on the weekends. All guns were loaded with 00 buck.
I stepped off 30 feet, put up our shotgun patterning targets, and let loose. Everyone of them has about a 6 inch pattern at 30 feet. The balls of shot ripped holes thru 1/2 inch plywood like it was paper. Each shotgun holds 7 rounds, the first 4 out the tubes will be 00 buck, and the last 3 are slugs. There is a wall at the end of the hallway, you go left or right to get into the living room. If needed, I'm sure the buck probably will, and the slugs will definately go thru the wall into the living room should some idiot try to get in my home.
Birdshot, I don't know if it will do the damage I am looking for, but I can only imagine a load of #6's to the face or any body part for that matter, should take the fight out of all but the most methed up fool that invites themselves into my house without my permission.
Just my thoughts. Yours may differ.