@flab are you suggesting a .45 acp has less penetration than a 9mm?
@flab Do you have any experimental sources for that? The significantly higher energy woukd seem to offset that, but im only speculating.
Ok so watched a few videos and, as expected, the actual answer is nuanced.
When shooting ballistic gel with no MDF, and using a FMJ bullet, then the 9mm indeed does have noticably more penetration. However if you are in a situation where you dont want deep penetration then you would be using hollow point...
When shooting hollow point on ballistic gel without MDF then 9mm and 0.45 ACP has exactly the same penetration. I t should be noted the 0.45 ACP while having the same penetration also did more damage to the gel in terms of cavity size... So in this particular test the .45 is superior as it has more stopping power for the same penetration.
When using MDF in front of the ballistic gel, however, we find the .45 ACP is significantly more penetrating than the 9mm.
so would seem that while the FMJ certainly gave results consistent with your claim, the more real world scenario of the hollow point in fact was counter to your claim and consistent with mine, that the ACP will be more penetrating than the 9mm.
Source for the hollow point tests: