As to the 300BLK, I have nothing bad to say, a SR30 w/ a QDC suppressor is a wicked little beast, be it subsonic or supersonic. For what it is intended to do, nothing else, including the 5.56, can.
A 110 Barnes TAC-TX can run 2100+fps from an 8.5", will expand immediately, and will still penetrate 20" of ballistic gel. Rather nice marriage for an effective SBR at close quarters. Likely best choice in such platform for home defense.
