The basic service rifles and carbines of WWII were reliable. So was the BAR light machine gun by then.
We're talking about the reliability and effectiveness of the very most basic weapons issued to our troops.
Heck, when counting effectiveness, the current Europellet (9mm) pistol, which has to use FMJ ammo, is much less effective in stopping than the old M1911 (the latter of which just happens to be the design I carry every time I exit my dwelling).
I agree. As a veteran myself, I often wondered about the decisions to move from the proven 7.62 to the not-so-effective 5.56. Back in WWII, if a German soldier took at .30-06 in the chest from an M1, he wasn't getting up from it. Even the British Enfield and Vickers guns using the venerable old .303 (7mm) would put a man down reliably with a solid hit.
I personally know troops who have shot insurgents several times with M4s at lethal ranges (less than 200') and they took the hits and kept fighting long enough to return fire. Those same insurgents hit with a 7.62 slug would be DRT. Full stop. There is a reason quite a few Marines and soldiers carried .357 revolvers in Vietnam. The reason was the stopping power. The 125 grain .357 traveling at 1400 FPS boasts 96% one shot stops on human torsos that are not armoured. The .357 is still the gold standard for handgun stopping power. Like you with your 1911, I'm a .357 guy. If I cannot do it with six, I need something belt fed. Plus, like a lot of guys I know, I favour a New York reload anyway.
Although I quibble that I'm a Facklerite instead of a Marshall and Evans type, so I don't trust their .357 results, I'm specifically and convincingly told their data is just not of high enough quality to support their conclusions (I haven't investigated for real because since I was a teen the M1911 has fit my hand like a glove, so it's weapon choice/shot placement first, followed by the natural choice of .45 ACP over .38 Super, which I'll note is not the equal of .357).
The Martin Fackler camp believes that at service pistol velocities killing scales with the number of holes poked in a person, stopping scales with the area of the bullet. And all things being equal, .45 is a lot bigger than .357.
However I note that that famous .357 load has a nominal velocity that's twice as high as .45 ACP, so maybe it really is disproportionately effective (note that only the 10mm has really duplicated or rather substantially exceeded its ballistics, even .357 SIG doesn't quite reach the .357 Magnum).
One thing that got me to wondering in this direction is the "unreasonable effectiveness" of ~.30 caliber ball (FMJ) ammo (e.g. including the .303, German 7×57mm and Russian 7.62×54mmR). Absent construction like the relatively fragile West German 7.62 NATO round, like e.g. AK-47 rounds it's going flip, at least partly, before exiting without fragmentation, and without dumping much of its energy unless it hits solid bone or the like.
Fackler's general thesis about wounding is that permanent crush cavity counts, "hydrostatic shock" and the like don't much or at all, soft tissue by and large gets pushed out of the way and snaps back. Note that he got his start in this in Vietnam field surgery....
But when I look at the temporary effects of a high power 7.62 or thereabouts slug, I note that in most any torso hit their radius is going to encompass the spine. So I've been wondering if their proven effectiveness on the battlefield is a combination of a potentially temporary shock effect on the CNS via the spine (plus of course the direct effects), followed by bleeding out etc. before sufficient medical care can be rendered. The first being the "put down", the second being the "stay down", or at least weak enough not to get back up and be effective.
For what it's worth, I believe the original specifications for 9mm NATO involve a higher pressure than standard commercial 9mm (effectively +P, i.e., probably not something to fire a C&R WWI Luger, but again not quite a .357 magnum).
We're talking about the reliability and effectiveness of the very most basic weapons issued to our troops.
Heck, when counting effectiveness, the current Europellet (9mm) pistol, which has to use FMJ ammo, is much less effective in stopping than the old M1911 (the latter of which just happens to be the design I carry every time I exit my dwelling).