>>63857815
>traveling at a slower speed
Largely irrelevant (and also not necessarily true universally, and frequently untrue dynamically)
>with nearly the same kinetic energy
Not relevant. For the most part, service caliber handgun rounds crush bullet sized holes in flexible tissues regardless of kinetic energy. Kinetic energy is a poor predictor of wounding capability, I don’t even bother to look at it most of the time.
>Is this factor significantly or meaningfully increased with a bullet that has 2.43mm larger diameter
In absolute terms, the difference in diameter between a .45 FMJ and a 9mm FMJ is about the same as the difference between a 9mm FMJ and a .25 ACP FMJ, so idk, you tell me.
In relative terms, it’s a 61.4% increase in frontal area. Poiseulle’s law would suggest that fluid flow ought to increase with the square of the % increase in cross sectional area, and while this rule is very difficult to apply to the human body in any kind of clean fashion, it provides some grounds for substance.
In JHP form, the best .45 hollowpoints expand to about 0.79” average diameter versus 0.59” diameter for the best 9mm hollowpoints. In absolute terms, ask yourself whether there is a difference between a 9mm FMJ, and a 9mm JHP that expands to 0.55”. If you don’t think so, then bear in mind that the FBI’s 147 gr Gold Dot G2 only expands to ~0.49”, and +P 135 gr Critical Duty only expands to ~0.53”, so by that logic, the FBI’s JHPs don’t provide a meaningful terminal improvement over FMJ. In relative terms, the % increase in diameter is similar to Gold Dot G2 compared to FMJ - so again, if you don’t think that makes a real difference, then neither should there be one between 9mm Gold Dot G2 and FMJ.
