The whole "9mm/40/45/357 Sig" are equal phrase is not entirely true. If one cherry picks the data, perhaps, choosing the best loads for the smaller rounds, and picking inferior rounds for the more powerful cartridges, and most importantly, throwing penetration out of the window and focusing purely on expansion.
Probably the greatest misinterpretation of the IWBA protocol is that 12 inches of test gel is just as good as anything up to and including 18 inches. The tests preferred 18 to 12, not the other way around, with many people worrying about the non existent over penetration potential at 18 inches, and cartridges failing to hit 12 desperately wanting to believe their load still qualified by the standards. Far to many pocket pistol shooters want to believe that .380, .32, .25. even .22 hollow points, and that "magic" over expanding super bullets that only punch around 11 or 10 1/2 inches are still great rounds. If you really want to look at the iWBA protocol, realize that if you were to grade penetration gel tests, 18 inches would be A+, and that 12 inches is D-. 12 inches isn't good penetration, it barely qualifies at all for official test purposes. Your 90 grain HP .380 that only dug in 11 inches didn't "penetrate well" it failed the test completely. It was the dunce that failed the class and got sent home.
Digging through ballistics tests, from various sources, official and independent alike, the problem plaguing 9mm and .38 special rounds still exists, in the fact that improved bullets still have a potential to under penetrate, and often times when they do qualify, it is at the very base low end spectrum of the scale, often times barely crawling over the 12 inch mark. Many of the vaunted "super bullets" that many shooters talk greatly about, namely those that expand violently and up to .80+ inch, and indeed work in perfect conditions and very shallow shots, often times fail in angle shots and through limbs and fail to penetrate deep enough. The people who brag about 9mm 115 grainers that expand up to .90 inch in gel tests are the same people who fail to mention the bullet was pulled 10 inches out of the block, and has serious liabilities in the real world.
When one compares bullets and loads that expand to around the same diameter, you will find discrepancy, mostly on weight. The 9mm 115 or 124 that expands out to .67 will often barely manage to tip over the 12 to 13 inch mark, whereas a controlled expansion .45 230 grain will often end up 15 to 18 inches in the block. Rough estimates, but take the time to do your own research, and let me hear. The base point is, yes, you may get a smaller caliber to expand just as broadly as a larger caliber, but no, the lighter bullets will punch no wear as deep, and will perform far, far, far worse against bones and skin, considering both momentum and sectional densities.
The .40, 45, and .357 Sig all can do more than the 9mm can, and to claim parity is dangerous. The 9mm was ditched because it will fail in extreme real life angle shots, and has failed in real life angle shots. Pistol rounds have been dug out of bodies mere inches away from internal organs, sometimes fractions of an inch away from killing effectiveness. To discard the difference of 3-4 inches of penetration could very well cause a failure to stop in many instances. The heavier round will punch deeper, and break bones and spines, instead of simply curling up to take a nap against them like a lighter bullet will.
Certainly this thread, which I'm surprised was resurrected from the dead, is filled with people who hate the FBI because they buried their beloved caliber back the late 80's. But 9mm's extreme proponents are as bad as any other calibers, and recite the same myths, and over exaggerate the effectiveness and advantages of their beloved caliber. "Its just as good, with less recoil", is not nearly true at all, completely ignoring that there are very real advantages to the heavier recoils of the larger rounds, also making grand assumptions that .40, .45, and .357 Sig are somehow impossible to control, compared to the easy shooting 9mm.
What seems to be a big idea here, and elsewhere, is that because a 115 9mm +p+ can do 1350 fps, it is automatically just as good as a 125 grain .357 magnum or Sig doing the same velocity, completely ignoring the 115's reputation to fragment and under penetrate, compared to the heavier 125, with better sectional density and sheer energy.
The truth is, the full power 147 grain is every bit superior to lighter 9mm bullets, as the 158 grain .38 specials were before, to lighter bullets, for pistol rounds need every bit of mass and sectional density to work correctly. But to do so would be to lose the super expansion, the higher velocity, and the hollow ideas that make the 9mm seem as good as the other calibers. Proponents of the lighter bullets still hold onto, and repeat passionately, the debunked junk science of the 20% 1970's style gel tests, temporary cavitation, and the pistol theory of light and fast.
Just as .45 ACP's worst proponents desperately wish to believe their caliber is an automatic one stop shot, so to the 9mm's truest believers wish to believe their caliber is just as effective as rounds far more capable than their own, refusing to accept that their advantage lies in lower recoil and capacity, at a cost.
Every person who can be called a caliber fanboy shares the same personality defect of having no problem with ignoring shortcomings and exaggerating or even inventing strengths, instead of simply accepting there are advantages and disadvantages to every caliber and many loads. The fanboyism in this thread enraged me enough to write all this giant post.
