The 125 grain hollowpoint police loading in .357 has lots of evidence to show it was the most reliable one shot stop defensive cartridge. The industry has changed so much since then I'm not sure that still stands.
This is said quite often, that the top one shot stopper is the .357 Magnum with a 125 gr. bullet, but there is only one source for this information and that is the writings of Evan Marshall and Ed Sanow and they did not directly say that.
Set aside that their results and opinions are very controversial and let's see what they say.
In there last book, 2001 "Stopping power", they give the Federal and Remington 125 gr. JHP rounds a OSS rating of 96%. But the Winchester 125 gr. jhp they give a 87% rating. So it's not all 125 gr. loads it's only some and it depends on the bullet type and velocity.
In the same book they give the Federal 115 gr. 9mm+P+ JHP a 91% rating. They allow the Winchester 9mm +p+ 115 gr. a 90% rating. Which is higher than some of the 125 gr. .357 magnum loads. Bullets with 124 gr. and 147 gr. jhps do worse according to them.
For the 45 acp they give the 230 gr. Fed. Hydra-Shok a 96% rating and the same for the 185 gr. Rem Golden Saber. They hand out a 93% rating for the 230 gr. Speer Gold Dot.
So they place some loading of the 45 acp on a plane with the .357 magnum and ahead of some loadings of the 125 gr. .357.
By the way they rate the "best" 10mm at 90% OSS.
The "best" 41 Magnum at 90 %.
The best 40 S&W at 94%.
This was in their last book after years of criticism. They had backed off some the idea that the 125 gr. 357Mag was the "best OSS round". They had always held that only specific bullets from specific manufacturers met that criteria.
But the whole idea was off base anyways.
I think if you decide on what you want to do with the gun (defense, hunt, back up, etc.) then look at the size and type gun, select a bullet that can do what you want it to do, then select a round you can shoot well from that gun, in most cases you will do well.
tipoc