Turns out my little brother, the police chief, has been sand bagging during my talks with him about .223 AR-15s. You guessed it, that is the department issue long gun. According to the ex-marine officer I spoke to this morning the round is a penetrator and does not by design tumble in flight or on impact. My brother the chief added that if it did the suits against the department would make national news.
So the research continues.