Just found this thread, and seeing as it has been brought back to life before, I figured I’d necropost as well, since I have some findings on this issue.
In North Carolina where I grew up the deer are so numerous that the state doesn’t even require depredation permits for taking deer that are interfering with crops or plantings, and there are no caliber restrictions against common handgun chamberings. Therefore, I have taken a good number of deer over the years using my 2 handgun calibers; .45 GAP and .357 Sig.
While I don’t feel comfortable using 9mm on deer (I also don’t own anything in that caliber), I have hunted with folks that do, so I have been able to make comparisons of the effects that these handgun calibers have on large living targets (100 to 250 pounds) with a pretty decent sample size.
The results are that there is really no contest; the .357 Sig both produces a much larger and more severe wound, and especially incapacitates deer much more quickly than the other handgun calibers; both damage and speed of incapacitation with the .357 (when kept within reasonable ranges) is more comparable to the effects of rifles I use (.223 with 62gr Federal Fusion softpoints and even .308 with 150gr Hornady SSTs). The .45 produced a large wound (much larger than 9mm but smaller and considerably less traumatic and deep than the .357) using my handloads of a 230gr Gold Dot at 890fps, but the deer shot with .45 never go down immediately with that instant incapacitation I see with rifles and the .357.
The rounds I use in the .357 Sig are the factory 125gr Speer Gold Dot (about 1400fps from my G31), Federal HST 125gr (about 1375fps), and my own handloads pushing a 125gr Speer Gold Dot at 1500fps. While of course the results are the most impressive with my handloads (hot velocity, but only 34,000 psi with 9.6gr of 800-X), even the factory loads still blow the .45 out of the water.
The 9mm loads I have observed are Speer Gold Dot, Federal HST, and Winchester Ranger, with bullets in 124gr and 147gr weights and both standard and +P pressure levels. When using handguns, we always take the standard “boiler room” heart/lung shots, and keep the shots short (50 yards with the .357, 30 yards with the other rounds). While neither my hunting partners nor I have ever lost a deer (the closest I have ever come to losing one was actually a .45-70 that was deflected by a leaf from my point of aim of the lungs to a gut hit), the deer hit with the 9mm always run, as far as 200 yards and averaging 100 yards. The ones I shoot with the .45 also always run, but generally don’t make it 50 yards. At least half of the deer similarly-hit with the .357 go down and stay down, with the rest usually only going a few yards, out to a max of 30. That’s pretty much what my experience is with the .223, and is similar to the .308, except that fewer than a quarter of the ones I hit with the .308 get up after being hit.
On the mechanics side I don’t like to theorize or extrapolate much, and I don’t know whether it is a ballistic pressure wave, hydrodynamic shock, or anything else that makes the .357 Sig produce the much better incapacitation results I have observed, but what I can say is that there is a large quantitative and qualitative difference. My thinking, though, is that it is rather simple; energy is nothing more than the ability to do work, and the .357 having more energy and expending it all within the deer (nearly always the bullet is trapped by the hide on the opposite side, occasionally on smaller deer it goes all the way through) just performs more work, i.e., damage, in the medium where its energy is used.
Whether this rapid and consistent incapacitation is the result of a ballistic pressure wave or simply the considerably larger amount of tissue being destroyed is beyond my ken, but the much greater efficiency, and particularly speed, with which the .357 Sig puts down 100-250lb animals with center-of-mass hits compared to the other duty handgun rounds does give me great confidence that it is indeed a better choice, at least for me, for self defense.