I suggest everyone plan for a big day with a few buddies and get to some open land and setup different scenarios and different material to shoot through and come to your own conclusions.
While a good approach in theory, it has one glaring problem: you can't replicate the effect of shooting into living flesh. Any test medium used is, at best, a poor approximation. This is why the debate rages to this day between the "morgue monsters" -- those like Marshall and Sanow, who use shooting statistics to try and determine stopping power, and the "jello junkies" -- those who support lab tests with ballistics gelatin, like Dr. Martin Fackler. The insulting nature of the nicknames they call each other is some indication of how rancorous the debate has gotten.
The problem is that both sides are partly right. Marshall's and Sanow's methodology is rather suspect, and real life shootings have so many variables from one incident to the next that its all but impossible to draw firm conclusions about stopping power. On the other hand, while lab tests with gelatin can be strictly controlled, and variables eliminated, the fact is that ballistics gelatin is very, very far from a perfect approximation of human flesh; it's homogeneous, while the human body is anything but -- being made up of flesh, bone, blood vessels, organs, viscera, etc. and they all vary so much in density, texture, strength, elasticity, etc. that gel can't ever give you better than a crude approximation of how a bullet will perform when it enters a human body.
Any test medium one uses at home, whether it be phone books, clay blocks, pine boards, ham hocks, etc. is going to be even less ideal a stand in for human tissue, and most people, being ill-trained in research methodology, will not be able to control very well for all the variables. People who don't have a thorough understanding of how to conduct scientific research typically have their results skewed by uncontrolled variables, confirmation bias, faulty premises, or other factors. This really is one area where, unless you have specialized training in how to conduct rigorously controlled and scientifically valid tests, you may honestly be better off deferring to the opinion of experts.
Determining who are really the experts, and who aren't, however, isn't easy. For that, you have to do a lot of research, and use your best judgment to critically analyze competing claims.
Now of course, having said all this, there's no reason that you can't conduct your own tests, and add that to your knowledge base. Just be aware of your own limitations, especially if you get wildly different results from what experts seem to be getting.
:banghead:
