Years ago I was able to do some ballistic research and came up with a short non-definitive study.
I was fortunate in my LE career to be forensic trained. In that time I attended many autopsies, and was able to assist with many.
What started my ballistic research...One time I was waiting for a victim of case I was working to be done, but there was a gunshot victim from another agency before me. I was allowed to watch, photograph and have them slow down to examine the entrance, bullet path etc. Once that was over I asked if at any time they had a gunshot victim to please call me any time day or night, as I wanted to do my own research on the subject.
I was also fortunate to be able to do the same in a neighboring state at their lab, both were extremely helpful and knowledgeable and provided me with a lot of valuable information about what I was doing, and went out of his way to make this research possible.
Overall I was able to attend and document 42 shooting victims in a span of almost 5 years, from 2003 to 2008. Examine bullet entrance and exit, if there was one. Bullet path, damage, and projectile diameter, weight and make, model ID.
I also gathered data from LE shootings from NW agencies and added what I could into the research, because I was able to positively ID the bullet make and model and some information as to the victim size, weight, distance of the shot and angle etc.
Some of what I learned, I never found in any book on the subject. I have read most every book out there about ballistics, even the famed Stopping Power book by Marshall & Sanow, which I thought was lacking.
What I learned;
Pistols don't produce enough power to effectively have consistent bullet performance. aka pistol bullet performance sucks.
In talking with a friend of mine who's an engineer for ATK, but overall works for Federal - Speer - CCI, creating a HP round is a delicate matter. If the velocity is too great, the HP opens up too fast creating a parachute affect, thus not getting penetration. If it goes too slow, the HP won't open up and will act like a FMJ.
Folks don't realize the differences in each human that can affect bullet performance. Things such as age, medications, drug use, smoker, weight, muscle density etc., all have affect on skin, organ and bone density...which affects bullet performance. Even race, culture and place of residence around the world have some bearing. This information came from one of the Dr's which spent many hours with me going thru this part of the study, showing me the differences...fascinating...to me anyway.
One can shoot 6 different people in the same place, with the same caliber and bullet and get 6 slightly different results. Why 6?, because I witnessed it myself through the autopsies.
Some bullets were hard to identify as to make and model, but others were readily identifiable. After a few victims where I was able to identify the bullet, I would receive a call now and then from a med examiner asking if I could make an ID for them.
A person can be shot through the heart, and sometimes totally destroy the heart and still live over 2 minutes. A lot of damage can be done in that amount of time.
9mm is what I found to be the absolute smallest pistol caliber to use/carry. And #4 or #6 shot is way more effective than 00 Buck. Yes, I know .22 rimfire and other small calibers have killed many a person, but the smaller calibers needs even more emphasis on shot placement.
9mm = .355"; 40 = .400"; 44 = .429" 45acp = .452"
Stay away from the gimmick bullets, and go with a solid constructed HP. What works in ballistic gelatin, wet newspapers, even live or dead animals is not the same performance you'll see in human media.
Bonded bullets work well when going through media such as glass, boards etc., but lack consistent performance when entering a human without going through the above first, won't get consistent reliable expansion.
Finally, shot placement is paramount...Period! If a bullet doesn't go in the snot-locker, you'll be waiting for the person to faint. Yes, that is the medical term for someone who loses enough blood pressure...they will faint. More bullet holes, equal faster blood loss, which in turn lowers the blood pressure until the person faints. So the ultimate goal of such a confrontation is to have the threat faint really really fast...unless there's the snot-locker shot.
Another person I relied on was Dr. Gary K Roberts. He came to our state LE firearms instructor conference some years ago and made a ballistic presentation, and I was able to compare some things with him, and confirm some of what I was seeing. What I liked about his presentation is that it dispelled some of the myths in the firearm ammo community. Attending his presentation were some ammo manufacturer reps we had there, they were not happy to hear that some of their product was junk.
My study is in no way definitive, but each autopsy and other shooting info kept proving the above...and gave me information that I felt was not available to the public.