"I am asking what you all think about this caliber."
It is one of the better options currently available.
1870s - Catridges looking a lot like the .40 and 10mm began to be worked on. The .38/40, as an example, pushed a 180 grain bullet at approx 950 feet per second. Not bad for black powder.
1960s - Folks started looking for what they considered "the ideal" revolver cartridge, a .40 cartridge which could push 200 grain bullets between 900 and 1000 feet per second. Folks like Jordan, Keith, and Skelton, mind you. (They didn't get it, instead getting the more powerful .41 Magnum; a great cartridge relegated mostly to field use having been deemed too powerful by most for every day carry and defensive use.)
1970s - Col. Jeff Cooper, Mr. .45acp, called for "the ideal" semi automatic cartridge, one delivering a .40 caliber 200 grain bullet at 1000 feet per second. The 10mm began to take hold. (He didn't get it, instead getting a more powerful 10mm; a great cartridge... deja vu... deemed too powerful by most for every day carry and defensive use.)
The 10mm began to be loaded in two varieties; the magnum variety which has proven popular with 10mm advocates, and the variety often referred to as the "down loaded" and "lite" 10mm. (The weaker cartridges look an awful lot like what the greats had called for, but what did they know?)
1980s - the FBI adopted the 10mm in the form of a 180 grain JHP at approx 950 feet per second. There never was a stronger one or a weaker one. That was it, and the agents apparently liked it.
Meanwhile, folks began experimenting with cartridges duplicating the 10mm. And someone asked, can we produce a 9mm sized semi-automatic with a 10mm performance? Yes, was the answer, so long as you are talking about the "lite" loads, the self defense loads, the loads closely mirroring what the greats had called for. The .40 S&W, bout a 0.140 inch shorter than the 10mm Auto but otherwise nearly identical, was introduced in 1989 with a 180 grain loaded to identical specs as the FBI spec'd 10mm.
The .40S&W currently dominates the US law enforcement market, having captured between approx 70-75% of the market.
It is very popular with the self defense and gaming crowds, too.
Why?
LEO wise: Many law enforcement agencies took note of the FBI's delaration that a 10mm 180 grain JHP at approx 950 was "best" for LEO/SD purposes. And some of those folks were gunnies who rememered what hte greats had called for.... They also took note to the .40 S&W pistols duplicating that is 9mm sized pistols, with nearly splitting the differnce in capacity between the 9mm and the .45acp. The combo of of good performance, with smaller pistols, and increased capacity was all that it took.
Gamer wise: 180 grain bullets at 1000 feet per second make major. Making major while affording more capacity? That's all that it took.
Non-LEO/SD wise: These folks, many of them at least, pay a lot of attention to the afore mentioned folks; greats, LEOs, and gamers. They began to see more and more pistols chambered for .40 S&W, and that's all that it took.
Now a days, there are a variety of choices, with the 155, 165, and 180 grain varieties being the most popular. Gaming and bipedal fighting wise, you could do worse.
The two law enforcement entities who spend the most time and money testing such things, both primarily issue .40S&W offerings, the 155 grain JHP and the 180 JHP respectively. That doesn't mean there aren't other worthy options, or that they are the only ways to go. But its indicative that perhaps you could sleep well at night with a gun loaded with one of them in your night stand.
So for my money I'd advise ignoring the nay sayers, or at least understanding where they are coming from - allegiance mainly to the 9mm, 10mm, and .45acp crowd. They're good crowds to be in, for sure, along with the .40S&W crowd. They're just a bit resentful at times at the upstart eating into their pie. Oh, and you should hear them infight among themselves.
