Ok so now we're worried about a little bit bigger expansion, I thought a little more expansion was insignificant and that recoil and penatration were the key.
I don't know how you got that out of my post given that it was about the failure of the .380ACP to meet the commonly accepted
penetration threshold with self-defense ammunition.
For what it's worth, since the vast majority of handgun "incapacitations" happen because the person who is shot voluntarily gives up (psychological incapacitation, not physical incapacitation) I would expect the .380ACP to provide very similar real-world results to the 9mm and, indeed, the rest of the service pistol calibers. Greg Ellifritz's data bear that out. In his analysis of real-world shooting. the .380ACP compared very well with .45ACP in nearly every category.
Of course, that doesn't tell the whole story. There is a difference and that difference comes into play when one needs the penetration that the FBI states is the minimum acceptable amount. That doesn't happen very often in the real world but it does happen and when it does, the .380ACP can't reliably deliver.
Does this hold true if we are discussing full "duty" size handguns and barrels or is it primarily a concern out of pocket pistols? Since we are making an argument that expanded bullet diameter differences are insignificant and penetration is key what about with FMJ rounds?
All of this is predicated on a discussion about typical self-defense ammunition--in other words, expanding ammunition.
There does seem to be consensus that FMJ/non-expanding ammunition doesn't provide incapacitation results comparable to expanding ammunition. My personal theory is that the primary benefit of expanding ammunition is that it provides rapid "notification" to the person who is shot that they have been injured while FMJ bullets sometimes create injuries that are not rapidly noticed by an adrenaline-enhanced attacker.
What finally occurred to me: the arguments for 9MM are based on time of aimed fire - time differences that are measured in small fractions of a second.
Well, if you're really taking accuracy into account, the difference can't be in time alone unless the course of fire is reasonably challenging in the accuracy department and the times are compared ONLY when accuracy scores are identical.
I've done some comparisons in matches where there are multiple targets scored for accuracy and time is also taken into account and the differences aren't "small fractions of a second". The scores (combination of time and accuracy) in categories shot exclusively with .45ACP and 10mm pistols show an average of 20% degradation compared to categories shot mostly with 9mm pistols. Master class shooters' scores also showed a degradation in performance, but only about 10%.
http://thefiringline.com/forums/showpost.php?p=6298075&postcount=76
A truth I am aware of. However I am not, and likely never will be, good enough to deal with multiple determined and competent attackers.
If that's your threshold then it doesn't really matter what gun you carry or what caliber it is. You're not just accepting the possibility of a psychological stop, you're banking on it.
The odds are pretty good in your favor--over 90% of stops are psychological--but then the odds are pretty good in favor of your never needing a gun in the first place.
If you're concerned about caliber, then, by definition, you're talking about less than 10% of self-defense gun uses since over 90% of the time the gun isn't even fired or the attacker isn't hit or injured seriously. Obviously caliber can't play any part in that kind of an encounter.
but what do they know.