Now, with improvements in cartridge and bullet development in 9mm and .45 ACP, and advances in gun design, it has become less relevant. I have transitioned away from the .40 in favor of the .45. I can get equal or better performance with a low pressure round that produces less recoil in my guns.
This is a reasoning I don't understand.
1. Chamber pressure is NOT a decicive factor in level of recoil. If it is, then 9mm should have more recoil than a 45ACP.
2. Sure, 45ACP has less chamber pressure. But,recoil force itself is still large, meaning if fired from same model of guns, like M&P40 vs. M&P 45, it's not as if 45ACP version of the similar model pistols have a longer service life. Of course, some love to say "45 is more of a push than a snap," which is totally subjective and not in any means universal. Sure, recoil from a 40oz all steel 1911 felt okay, but 45ACP Glock felt plenty snappy to me. But, 40S&W SIG P229 felt even milder than either of my full steel 45ACP 1911 to me. That does not mean I go around spreading "45ACP is snappy while 40S&W is more of a push than a snap" nonsense.
3. 40S&W critics just love to say "9mm, 40S&W, 45ACP, they're all the same." If that's true, then the only sane choice is a 9mm, but a lot of them loves to make an exception to 45ACP which is even more expensive and even less capacity.
Also, there really is no technology that can measure the power benefit from 40S&W or 45ACP over a 9mm. But, the critics just love to change "benefit cannot be measured" to "there is no benefit."
They just cite the gel tests, but ignore that more powerful bullets tend to crush through bone and get deflected less.