I don't think a human skull or throat would react any differently than what you've described happening to the deer.
It's more how #6 - even high brass loads, are going to react when hitting a leather jacket, a sweater, a few inches of fat and an inch or so of muscle...
Is it going to get all the way back to vital tissue?
It might, against some people it might. But probably #6 is not going to reach the vital tissue consistently, and not against a large percentage of the population.
If I knew that the only people who were going to break into my house were scrawny characters 10" from front to back, and that they were only going to be wearing T-shirts, and I absolutely could accurately put my shot right where their heart was...
I'd still use #1 Buck
