I do not think that, for several reasons, police officer rounds fired in a "gunfight", data would be the same/similar to rounds fired by a civilian exercising self-defense.
Sometimes you get what you pay for, sometimes you only pay more for what you get.
Three shots are not a "group"...they are a "few".
If the Bible is the literal, infallible, unerring word of God...where are all those witches I am supposed to kill? (Exodus 22:18)