Lots of testing has been done on this, any round that will stop threats reliably will penetrate drywall, end of story. Testing also shows that 223 penetrates less than 9mm. Use angles to your advantage and don't miss.I know I am about to offend some of you, however if you live in a residential neighborhood a 223 is not ideal for home defence. You are firing a round that can easily penetrate your drywall and siding and then your neighbors and kill someone next door or down the street. Unless you live in a log or all brick home, a hi velocity rifle round in a neighborhood is a safety hazard. And you need to make dang sure you don't put a round through a window or door.