It’s reached a point where 9mm ammunition is the cheapest centerfire cartridge available. When I was younger, that title belonged to 38 Specials – but somewhere along the years, it moved to the old 9mm parabellum. Back in the revolver day, it made sense (at least to me) to have a revolver and a lever action carbine in 357 magnum – where I could feed either with 38 specials or 357 magnums. Now, as revolvers have given way to semiautomatic pistols, the default option is 9mm.

https://www.americanrifleman.org/content/8-reasons-to-invest-in-a-9-mm-pistol-caliber-carbine/
The chart shows the power advantage that a carbine has over a pistol – and the carbine makes hitting the target a bit easier. The next chart shows the differences between velocity based on barrel length for the 357 magnum.

Since velocity correlates with power when the same bullet weights are used, that 16 inch barrel offers about 17% more energy than the 6-inch barrel on my revolver. Going back to the 9mm, the carbine bounces the power up by about 46% over the pistol (and it’s worth mentioning that my 9mm pistol barrel isn’t quite 4 inches long).
A century and a half ago, the combination was in 44-40 – the Colt Frontier revolver and the Winchester model 1873. That carbine showed the same 17% advantage as the 357 magnum charts – the bottom line is that the longer barrel offers more power and is easier to hit with. The combination in the same caliber meant that the same box of ammunition could feed both rifle and revolver.
Occasionally, someone asks about the best pistol cartridge for bear country. I’ve never had to deal with a bear attack. I have had a fistfull of 22, of 38, of 357, and of 45 when I’ve been fairly close to a large grizzly – if you go back and click the link, you will quickly see that no handgun fills me with absolute confidence. Despite that, it is easy to remember that Bella Twin used a single-shot 22 rifle, with 22 long (not even long rifle) cartridges to take the world record 1953 grizzly in Alberta. This photo shows Bella Twin’s bear rifle:

Robert Ruark wrote the book Use Enough Gun. The chart below suggest that a big part of using enough gun is having a long enough barrel.

At any rate, there is an argument to be made for pistol caliber carbines – whether in bear country or facing a paper target. My own, from the pre-cataract surgery days, is a Hi-point 9mm with a simple red dot sight added. It isn’t enough gun – but it beats praying.