"Dead" overstates the .40S&W's
present condition. The .45GAP, like the .38 Casull, is a dead round, except maybe to hobbists and collectors of odd-ball cartridges.
It's more accurate to say the .40's "dwindling rapidly" since being abandoned as a "service cartridge" in favor of the 9mm by major law enforcement agencies at the federal and state level. Even so, it will be at least a decade before any retrospective "autopsy" can be performed and the .40's death as a common handgun cartridge determined with any reasonable certainty.
Just take a lesson from the .40's parent cartridge, the awesome
10mm AUTO.
The most disrespected handgun cartridge in history, the 10mm has been declared "dead," or written off as a "dead round," at least 50 times since its first alleged "death" in 1986 or '87 - like, what?
44 years ago! - and yet the Big 10mm's come back swinging every time. It's the ultimate revenant of the ammo world!
With all the shortages of firearms , I have a good deal on a sig 229 enhanced elite in 40 caliber. But it’s being avoided like the flu. I’m thinking that the 40 is dead.
Nope, get a steal-of-a-deal on the 229, if you can. Even if .40 factory ammo disappeared tomorrow, you can easily make your own by reloading. There's tons of NOS dies and .40 brass around, and .40-cal/10mm bullets (jacketed and hard cast) are ubiquitous.
Forte S+W sig-lined:
[The 10mm AUTO] is the perfect example of a Zombie Cartridge. Allegedly it has been dead since [1987], yet it continues to walk among us.
There, fix it fer ya. You can thank me later.