mountain man13. rock slat??? You should not be looking to piss of or wound anyone that does not belong in your home. And light weight low brass bird shot can be just about as wrong. You should want to kill them. No playin around. Just asume they my be on angle dust or all methheaded up and not thinking about the pain.
Depending on your home constrution type, distance to your neighbors home and the slug your useing a full bore slug could very easily end up in your neighbors home some where half way across it.
A shoot over looked is the very heavy tungsten shots used for duck, turkey, coyote with shot size for #5 to BB which is .18 cal and T which is a .20 cal with weight from 1 1/2 to 2 3/8oz. This shot could be a better choice for a BG when neighbors and other family member are a concern.
It is very possible to miss a BG in a hall way of a house with out aiming a shotgun so practice is a most. No point and shooting from the hip at inside house distance.
The 55gr fmj .223 is better than many pistol rounds in a house as the bullets tend to key hole and come apart at the high velocitys when hitting drywall.