Well I know a guy who claims a head was the reason he lost a special deer and has pretty much devoted his archery life to testing and designing one. He still seems bitter over it and has also been bow hunting since at least the 70's. He just failed the rocket miniblaster expandable head. He does put them through some crazy tests.

You can find most of his test here:

http://btreviews.proboards57.com/index.cgi#general

On a personal note I was with my brother last year and I would blame a problem he hadwith a big 8 on the head he used. A great vital zone shot that headed south through the gut. We found the deer but lost the meat.

I like to tinker myself but have a differnt idea of what is right.