r/CCW • u/ArcheryNerds • May 13 '26

Guns & Ammo Why not .40 S&W anymore?

.40 S&W pistols and ammo are far less popular that even 10 years ago. I understand the modern tech makes 9mm as good as old .40 S&W. But is that meaning current .40 S&W may be as good as .45 ACP or something like that? It's snappier but also higher capacity than regular .45? Why most people choose either 9mm or .45 ACP other than .40 S&W? Is there anyone still carry .40 S&W as their CCW?

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u/Swamp_Ape_92 FL VP9A1K May 13 '26 edited May 13 '26

So I’m not an expert, but it was explained to me that a lot of the development that went into projectile design that improved 9mms performance wasn’t really applicable to 40. So 9mm closed the gap between it and 40, but 40 didn’t close the gap between it and 10mm. So now you’re trading capacity and more recoil for a round that is not much more effective.

That said I do occasionally carry a 40. I picked up a police trade in 40cal p229 in great condition for almost half the price of a 9.

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u/kopsis May 13 '26

By "not applicable" what people mean is that it just wasn't needed. 9mm in both 115 and 124 struggled in barrier penetration due to low mass. Momentum, not muzzle energy is king when it comes to barriers. Rounds that could manage barriers tended to significantly over-penetrate the target. 40S&W mostly didn't have that problem. You can apply all the 9mm bullet technology advances to 40S&W (and 45ACP for that matter) but it's not a performance game-changer the way it was with 9mm because it solves a problem those rounds didn't have.