I think a little history lesson is in order here. .45's were first adopted by the U.S. Military in the 19th century. Back then it was not the .45 ACP but rather the .45 Long Colt and .45 S&W Schofield cartridges. Part of the reason that the army chose such guns was because, in the days of blackpowder and relatively low velocities, the big, heavy slugs were effective not only on people but also on horses (remember the primary users of handguns were the cavalry).
Fast forward a few years to 1892, the army and navy decide that they want a more modern DA revolver and they choose the Colt M1892 in .38 Long Colt, a rather aneimic cartridge by todays standards. At first, the .38 is satisfactory in dealing with the Spanish. Theodore Roosevelt said that the Spaniard he shot with his .38 at San Juan Hill "crumpled like a jackrabbit". However, a few years later trouble arises when opium-fueled Moros don't seem to crumple when shot with .38's. To be fair, issues were also encountered when the Moros were shot with 30-40 Krag rifles as well, but the handguns recieve the most attention.
It is decided that the .45 is to be re-adopted and it is for a short time in the Colt M1909 New Service revolver. A couple of years later, John Browning comes along with this new-fangled semi-automatic handgun which fires a cartridge that give nearly identical performace to the .45 revolvers. The army decides that they like it and the 1911 pistol is adopted. All is good since there isn't any sort of armor than stops bullets very well and the cavalry is still alive though in its twighlight. Everyone is happy through WWI.
Now we're into the 1920's and 1930's and we start to have some problems. The .45, while still good for people, is starting to have problems when those people are gangsters or bankrobbers sitting inside these new fangled automobiles. A couple of different solutions to the problem are devised. Colt chambers their 1911 for a new cartridge called .38 Super which has little trouble going through these new fangled autos and S&W introduces the most powerful handgun yet devised with their .357 Magnum revolver.
Now, we get to 1935 and John Browning yet again comes into the picture. That crafty old JMB produces what is probably the greatest enemy to the 1911 he fathered: the GP35 Hi-Power. This gun uses that infernal Teutonic 9mm cartridge but gee-wiz it carries almost twice as many of them as the 1911 does. Those silly Europeans seem to like that sort of thing, but we still like our .45's so we stay with them.
A few years go by an now we get to 1941 and this big, old mess called WWII. We need lots of guns so we make lots of them including lots and lots of shiny new 1911's in .45. We still like them OK, but we start to notice some things that we hadn't thought of before. Those pesky Nazi's like to wear steel helmets and sometimes our nice slow .45 bullets don't go through them. Likewise, that danged old Tojo likes to send lots and lots of Japanese soldiers and sometimes seven of those big, old .45's just aren't enough. Well we beat those pesky Nazi's and that danged old Tojo anyway but now those big, mean Russians are looking kind of scary.
Now we get together with some of those silly Europeans and decide to make an alliance in case those big, mean Russians do something nasty. We call this alliance NATO and we decide that it would be smart for all of us to use the same kind of ammo. Wouldn't you know it, those silly Europeans seem to like that wierd Teutonic 9mm and we start to think about it. Those big, mean Russians seem to like to send lots of people like that danged old Tojo did and they wear steel helmets and big, thick coats like those pesky Nazi's did. This wierd 9mm seems to be able to go through steel helmets and big, thick coats better than our nice, slow .45's and we can have lots more of them in case there are a lot of big, mean Russians. We decide that maybe the Europeans aren't as silly as we thought they were and that maybe this wierd 9mm isn't so bad since we can't find anymore horses to shoot. The problem is, we want new rifles and machineguns too and we've already got this shiny new 1911's. Well, we decide that we'd rather have new rifles and machineguns so we'll just keep those shiny new 1911's until they wear out.
Now we skip ahead about 20 years and we're in this nasty place called Vietnam. These funny little guys in black pajamas seem to like to fight with us, but they don't wear steel helmets or big, thick coats like those big, mean Russians do so our .45's still seem to work OK on them. The only problem is that lots of those shiny new 1911's aren't so shiny and new anymore and by another 20 years later, they're old and worn out.
By 1985, we're out of that stinky, old jungle and worried about those big, mean Russians again. Since we need some new pistols anyway and we have this nice President Reagan that doesn't mind if we spend some money on the military, we decide we can finally buy those 9mm's that we wanted 20 years ago. Most of us like these new fangled Berettas except a few old guys that say they don't feel as nice as those old 1911's did.
Now, we fast forward another 5 years and those big, bad Russians aren't so big and bad anymore. However, now we're in this hot sandy place called Kuwait and we start having some problems with our nice, new Berettas. Seems that some of our soldiers are using some big, bad ammo that those silly Europeans use in their submachineguns. That nasty stuff is breaking our shiny new Berettas so we decide that we should only use nice, mild stuff that won't hurt our nice, new guns.
Now we skip ahead another 10 years and we're back in some hot, sandy places called Afghanistan and Iraq. We have to fight these crazy little dudes who like to say "death to America" and talk about 70 virgins all the time. Sometimes when we shoot these little dudes with our nice, soft 9mm's that won't hurt our Berettas, they don't just roll over and die like they should. Now, our soldiers, who sometimes like to gripe anyway, start thinking about the stories that their dads, grandpappys, and that old drunk who stood on the corner told about how great the .45 worked on Nazi's, Japanese, and Viet Cong. They start to think, "hey, if I had a .45 like dad, grandpappy, and the old drunk did, it'd be a death ray." So, they start to engage in one of their favorite passtimes: they gripe about the 9mm. What they unfortunately don't realize is that over time, dad, grandpappy, and the old drunk forgot that every once in a while, that Nazi, Japanese, or Viet Cong would have to be shot more than once even with the "death ray" .45 and that sometimes you had to use a rifle in order to dissuade the Nazi/Jap/VC from his current course of action.
So, what's the lesson to be learned from this? A handgun loaded with FMJ ammo sucks. A handgun loaded with JHP ammo doesn't suck quite as bad, but it still sucks. If you have to shoot someone, use a rifle or a shotgun. If you don't have a rifle or a shotgun, use the less-sucktacular JHP ammo in your handgun and remember that the BG might require repeat ventilation before he sees the error of his ways. If all you have is the super-sucktacular FMJ ammo, expect to have to ventilate the BG more than once before he re-evaluates his outlook on life (or perhaps death considering he's been ventilated).
in Nam. Semper Fi Do or die. USMC