must have been on pcp to keep coming at the cop!
I doubt that four 9mm bullet strikes to the arm of a charging 300 pound guy -- just running on his natural adrenalin -- would stop him immediately.
The head shots were the ones that likely stopped Brown.
Notwithstanding what the "expert" Dr. Baden said, I think the general idea is to neutralize the threat, and that requires that one keep firing until the threat is neutralized (or one runs out of ammunition). If Brown was still running towards the officer, the correct response was for the officer to keep firing. He would have had no idea if his shots hit his target or not.
I have a Ruger 9mm with a 30 round magazine that I take when I go 'downtown' to the VA and it suppliments the Ruger 380 that I always have in my pocket. (I'll not become a Reginald Denny)
I bought my first three guns the day after the Reginald Denny Incident.