I know it s an abstract question and impossible to quantify, but you know what I mean. The .40 caliber has been in use for more than 20 years. In that time it has been adopted for use by several law enforcement agencies, most notably the F.B.I. If the feds think it the the ideal round for their needs, why don’t the rest of us?
I think it is an interesting question. We usually cotton to government standards when it comes to firearms. Look at the lingering obsession with the .357, or our love of all things 1911, or the popularity of the AR-15. Why not the .40?
What is the .40, anyhow?
Unlike some cartridges, the .40 S&W’s origins are clear. Officially developed in 1990, the .40 S&W is relatively young.
Back in 1986, the F.B.I. was involved in a serious shootout. The agents, two of whom were killed, were out gunned — even though they outnumbered the assailants four to one. After, it was clear the F.B.I. needed something better, and they set to doing some tests. That’s an understatement — I know. You can read more about the testing here.
If you look at the report of the 1986 shootout, you will see a mix of .38 and .357 wheel guns. The shot count was limited by the available ammunition and the speed and complications of reloads.
So automatics seemed to be a good place to start. The 9mm was gaining in popularity, especially since Colt was about to loose their lucrative 1911 contract to Beretta and the M9 (a 9mm).
If the old 9mm was good enough for military service, shouldn’t it work for measly domestic concerns?
No. Bank robbers sometimes return fire from behind car doors.
Penetration, high capacity, manageable recoil
They ended up choosing something that didn’t even exist. The 10mm was just coming into vogue — Colt’s Delta Elite and the Glock 20 being two of the leaders in that market. But the 10mm is a hot round. The larger powder loads produce sharp recoil. And the length of the brass means larger magazines and larger handles.
But how do you get a projectile to pass the FBI’s ballistic qualifications without creating too much recoil for small framed shooters? After all, increased capacity is useless if the shooter can’t control the gun.
The typical 9mm JHP weighs in around 115 grains. That same bullet, in a standard load, would have a muzzle velocity around 1,250 feet per second. Fast. But the bullet was too light for most barrier penetration.
The typical .45 ACP JHP weigh around 230 grains. That same bullet, in a standard load, would have a muzzle velocity around 900 feet per second. Or slower. Heavy, yes. But too slow to penetrate many barriers.
The 10mm is, as anyone who has fired one knows, a beast. Too hot for most to handle. But if you back off on the powder load, and trim the extra brass from the case, you get the .40 S&W.
The typical .40 S&W JHP weighs anywhere from 135 to 200 grains (depending on how hollow the point is or isn’t). They are marginally faster–anywhere from 1,050 to close to 1,200 feet per second.
The smaller case size of the .40 means that the weapon itself can be built on a smaller frame–closer to the 9mm than the .45 ACP. So you can engineer an ergonomic service pistol, like the Glock 22. Otherwise, it seems like the benefits are marginal at best.
That marginal increase was enough to get the round past all of the ballistic challenges set up by the F.B.I. And that’s enough. It is worth noting that the 9mm and the .45 ACP are both capable of passing these tests, though their powder loads have to be ramped up accordingly (which translates into more recoil).
But how many of us need that level of penetration? I’d rather have a round that dumps its energy sooner.
All of this is open to a lot of debate. Do you believe in the knockdown power of the .45 ACP? Do you want the hydrostatic shock potential of faster rounds (illustrated by the red channels in the picture below)? Are you a proponent of shot placement?
This photo, which is cited on many forums and blogs as the result of the F.B.I.’s ballistics gelatin tests, shows that there is really not that much difference.
I think the .40 is a fine round. But I don’t own a gun that shoots .40 S&W, and I don’t plan to. I see the .40 cal in the same way that I see the .38 Super. Both were designed to meet very specific needs. Both are solid performing rounds that never really made a dent in the civilian market. Though they have made some dents in some bad guys.