This awful stuff in Colorado got me thinking. What can a normal defense caliber do against someone like that?
Say 5 rounds of 38spl, or 7 rounds of 45acp, or 10 rounds of 9/40...
Attempt a head shot? Dump the mag into the body?
As for the rounds you mentioned, nothing at all. Especially when it's worn by someone psychotic. I have to think a smart guy like this would have to know he needed plate, did he have it, I don't know.
Odds of victory small, death likely.