This quote is from an FBI report written in 1989 regarding the optimum sidearm caliber for LEO's. I found it on another forum and was impressed enough that I wrote it down. However, I failed to write down the name of the report. IMO this statement has validity.
"Any bullet which will not penetrate through vital organs from less than optimal angles is not acceptable. Of those that will penetrate, the edge is always with the bigger bullet."