Pretty sure the .40 will be around for a long time.
Visit Lucky Gunner’s YouTube Channel. He did a whole series (10part?) on mouse gun calibers from .22 through .380 with links to ballistic testing as well. His conclusions were that properly placed the mouse gun calibers were still effective deterrents. Always better than a shovel from the truck!
@MitchR Like @William591 said Lucky Gunner did a full series on the (mouse gun caliber’s) as people like to call them, and others have done the same. I think most will be around for quite awhile, reason being a lot of people have the smaller caliber guns, me included. 
I did a quick ammo search after reading the Field & Stream article. I didn’t realize there was 25 ACP in JHP. It’s essentially the same price as 9mm JHP.
Still, I feel like I should pick some up for the Baby Browning, just because. On the other hand:
I admit that my desire to own a .32 and a .25 won and now I’m not sure if I want to keep either. Not due to the article, but they take up space! 
Articles such as these are just silly page fillers and the main reason knowledgeable people often end up stopping their subscriptions to these dying gun rags.
First off, outside of the .45 GAP which was an unmitigated disaster every single one of the others are very viable cartridges with long history and huge numbers of firearms out there chambered for them. And all of them have hardcore fan bases that are not going anywhere. I personally like the .41 Mag quite a bit, a cartridge that does NOT deserve any of the ignorant nonsense that is often quote without any first hand knowledge or experience by hacks.
I love Jeff Copper as much as anyone out there. But I just trained a wonderful gentleman in his 80s that wants to have a firearm to protect himself and a .25 is just about all his hands can manage. Should I tell him to dump it?
Well, yes, that. I suspect some magazines are more in jeopardy of becoming obsolete than certain handgun cartridges. If Life magazine were still around today, it wouldn’t be around today. (With due respect to Yogi Berra.)
As for the Cooper quote, I file it under the same category as .45 vs. 9mm, but funny. Good for the gentleman in his 80s; I assume a first time gun owner? It’s never too late to start!
It is my humble and unscientific opinion that 2 calibres are necessary between 9mm and 22LR. Both 32acp and 25acp gone? I strongly doubt it.
We still have mice, no? 
I can still find cartridges for the .38 S&W (at least last time I looked prepandemic). Even the 7.62x25mm has a cult following. I don’t think most of those cartridges are going anywhere, although they might be harder to find or more expensive outside of reloading… sort of how it’s been for the last couple decades. I might agree with the 45 GAP being pretty much dead… but I think it was dead as soon as it hit the shelves.
Yes he is. I get a lot of those 70s-80s first time Gun owners. Many of them ladies recently widowed. For many with issues like bad arthritis and such even the .32acp is too harsh.
This particular gentleman has a Eibar Liberty from 1924. It’s in great condition and after we found him a good aftermarket magazine it’s 100% reliable. I have also trained a few folks with the tip-up barrel Berettas, which are particularly friendly to older females and those with hand issues.
I saw a fellow laying across a bar pool table dead. Shot wth a .25 auto over an argument.
IMO, the 25ACP and 32 ACP (both developed by John Moses Browning), and to an extent the 22lr, are speciaized firearms.
If you do some research into the firearms of special agencies in the US, Britain, etc. even dating back to WWII, the Vietnam War, and even into the 90’s, these calibers were used for particular needs using particular tactics.
Good post. As usual I disagree with some of the statements. The 380acp isn’t going away much due to new types of self defense amo, yes it’s hard to get and, yes it’s expensive. One box of it will last a lifetime with luck. Also disagree with statement
About the 32/H&R/327 mag. To include light recoil = wrong. They put the rimfire
5mm mag. Out of production and after a pretty long time started producing amo
For it again. Had a 5MM rifle when they first came out and I wish I had it back with
some other firearms I sold to get other firearms. Quite a few years ago I wrapped
Up a bunch of rifles in a blanket cause I didn’t have enough cases for all of the at once, off to the gun store we go to get something Else.
First of all at the age of 69 I’m a newbie (legal) gunowner thanks to the state of Indiana.
So I am quite thankful for the thoughtful and intelligent replies in this thread.
I am certain after reading all your replies, no calibers are going away soon, at least until they come up with as many calibers as brands of toothpaste on the market.
Personally, I’m embracing the small calibers, they fit well in my jeans pocket and I think I can resell them with some modernization.
Project guns small-caliber 22’s and 25’s - there’s 2 - 9mm in the queue a Firestar and a Lorcin (top right) - whoda thunkit
and I’m ready
That is a lot of gizmos and gadgets there brother @MitchR and you should put them to good use.
Having owned a 41 magnum my only comment would be that I never should have sold it. And regarding mouse calibers, research Mossad and the Beretta 71. Nuff said.