...Greg Ellifritz. He published his analysis of 1,800 shootings over a period of ten years on his blog under the title An Alternate Look at Handgun Stopping Power and as a somewhat simplified article in American Handgunner exactly a year ago. Ellifritz's data include shotguns (mostly 12 gauge) and centerfire rifles. It should be no surprise that they were far more effective than any handgun. The only thing that bothers me about Ellifritz's study is that, although he mentions statistical significance, he never quantifies it. Therefore, we can only guess how big a difference must be before we can attribute it to performance of the cartridge rather than random chance. Ellifritz says that failure rates between 13% and 17% for calibers from .38 special to .45 ACP imply that they are similar in performance. It may be significant that the failure rate for .357 magnum (including .357 Sig) is only 9%.
Here's one link to E's article:
http://www.buckeyefirearms.org/node/7866An interesting read.
It's simple physics that shooting a given bullet faster or a bigger, heavier bullet at the same speed will be more effective. However, physics can't determine whether small and fast is better or worse than big and slow.
I'm not sure I would agree with "more effective". I'd certainly go with "possibly more effective" but that isn't the same thing. (And given certain limits, I don't think it is right, though that is a personal opinion.)
For example, shooting a 50BMG at 3500ft/sec or 3800 ft/sec would make little difference in terms of wound ballistics at 200 yards, even though that 300ft/sec difference is quite a lot.
In a similar fashion, shooting a 9mm 124gr bullet at 1050 ft/sec versus 1120 ft/sec
might make a difference in effectiveness, but we don't actually know that. (And while I agree it does makes a difference in terms of kinetic energy and momentum, I don't actually think that difference makes an
effective difference in 9mm performance in terms of stopping an attacker.)
Pistol performance for physiological stops, according to the research I've read, generally seems to sum up to:
-given certain minimum performance characteristics (12" FBI standard, for example), physiological stops
only occur quickly with shot placement on CNS, and physiological stops do
not occur quickly with
any caliber/round type with shots
not on CNS, barring LOTS and LOTS of hits
-physiological stops
may occur due to the sum of all damage, but unless damage is in CNS, sufficient damage to create a physiological stop requires multiple hits and lots more time than we want to wait
-psychological stops will occur with any round effectively equally, and shot placement itself does not seem to have a major effect.
Pistol rounds simply are so bad at damage (compared to long guns, for example) that minor differences between round velocities create an
effectiveness difference of basically zero, as long as certain basic minimums are met, with regard to physiological stops.
(Occurs to me to add: "Physiological stop" means that the attacker is
physically incapable of responding, no matter their mindset or willpower. "Psychological stop" is when the attacker
chooses to stop their attack. Studies show that by far, psychological stops occur
much more often than physiological stops, which is why plenty of people have defended themselves effectively with .25s and .22s. Or by taking a shot that missed, and yet that was sufficient to stop the attacker anyway.)
Compared to more powerful cartridges, 9 mm has three advantages. They are controllability, magazine capacity and cost. Better controllability results in more hits in less time and fewer misses to endanger bystanders. Lower cost means that more practice rounds can be fired for the same expenditure. The benefits of greater magazine capacity should be self evident.
.327 magnum may be an exception to the rule "Nothing smaller than a .38" since it falls between the .38 special and .357 magnum in power. In a revolver like the Ruger SP101, it gives you six shots instead of five.
And yet----there doesn't seem to a difference between any pistol caliber, really.
The good thing is that it means (again, given a certain minimal performance level, that 12" FBI is a good generic measure), any pistol will do. And hey, .22s work for psych stops too.
Most of the time, for single attackers single shots (or less) are sufficient for a stop. I'm not saying that this is what people SHOULD use as the determining factor for caliber/capacity/round choice, but it does mean that it isn't like I can argue with someone who carries a Beretta Bobcat around as their primary CCW weapon. Or a 2-shot .38 derringer.
Not what I'd choose, but it isn't me.
(And for people who want to make certain they can manage physiological stops---again, other than meeting that basic minimum, everything else is up to your particular preferences of capacity, caliber, velocity, loudness, etc...)
