Go to this link and read everything. Start on the bottom of the page (earliest) and work up the pageto the latest update. Keep in mind that this is work done on the heaviest, toughest animals on earth. An arrow/broadhead that penetrates 15" in a Cape Buffalo isn't even going to slow down when going through a whitetail.

http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=forum;f=24