My main shooting buddies will absolutely not shut up about how "impractical" of a deer rifle my 20 inch AR-10 (308) with 5-30x scope is.
If I had a desire to kill a deer with it, that deer would DIE. But, uh, not exactly the point.
(Edit to elaborate/clarify: I don't have any particular desire to hunt, so I am annoyed that my friends insist on discussing the suitability of my long distance precision target rifle for hunting. That said, if I indeed did desire to hunt with it, it would be more than adequate for the task)
Yeah, heart and lungs are a much much bigger target, every bit as deadly, and not completely surrounded by extremely sturdy bone.