I live in Indiana and see houses being built with plastic siding, 1" hard foam sheets on the out side wall. Walls are both 16" and 24" 2x4's on center with 4" batting type insolation and 1/2" sheetrock. Houses must be 8' from the line so are 16' apart. You would be real surprised what #8 bird shot will do fired stright though at 10' not hitting a stud. Fired at an angle the shot that misses the stud will hurt or kill if it hits flush, dog, cat. or human. Look for the lowest speed round that will cycle your gun and not open over 5" at the max distant you will shot in your house.
Do not clear your house call a cop! Stay in a safe room with your people gun covering the door. If god forbid you have to shoot that should give you a couple of walls before shot could get to the neighbors wall.
I'm close to you, my house was built in 1922 and have the same horse hair plaster inside, outside aluminum siding over a wood exterior but not sure of it's thickness?? But I do know that the roof of my house is 1X3 white oak tongue and groove. They don't make them like this anymore!! Neighbors to the east,north and south at least 60-80 yards with a lot of trees and the west about 20 yards with mostly heavy brush. I'm more worried about the windows than the walls. Old house = big windows.I am 75 years old and started hunting a the young age of 8. I also spent time with Uncle Sam from 1968-75. Have seen people shot with a shotgun during hunting and war. It doesn't mater what you are using if you hit what you are shoting at they hurt. Distance is not a shotguns friend, the longer the shot the less likely you are going to do a killing shot. I have seen people using a doorway to shoot from and the fraiming around the door stopping the shot but away from the framing it would go through both outside wall and inside wall sometimes doing it's job and sometimes not. Very few if any shot made it through the far outside wall. Now slugs and 00 all bets are off.
AgreedI have seen a aluminum ladder fall through an outside wall on new construction home, going all the way through the wall into the inside. New houses and apartments are not made like the old ones. My house was was built in 1975 and I would bet that buck shot would not go through an outside wall and a slug might not. All outside walls are brick, 5/8" plywood sheeting, 1" hard insulation sheet, 4" batting insulation, and 3/4" sheetrock. All inside walls are 3/4" sheetrock both sides, 6" batting insulation (6" studs inside walls) nothing is min code like most track houses built in the 2000's. I know a few states have better codes but a lot of people do not know how their house is built, they think they do but most house are build to min code for max profit.
Let me say there is a lot of good shotgun instructors out there that have used the shotgun in battle. Most have not used a shotgun in the USA against bad guys in current house construction. A lot of the time, what won't shoot through old construction homes will go through new construction homes like a hot knife through butter. IMO a shotgun is the best gun to use inside any home if over penetration into another room or a neighbor's living space is a concern.