As has been said repeatedly, while the .357 125 gr. JHP is a pretty good load, it's not significantly more effective than any other good HP load in common service calibers. Heck, when much of the M&S data was gathered, .40 S&W didn't even exist yet, let alone some of the modern JHP's and stout loads that have made lesser cartridges real performers.
With the right load, you'll get effective performance with anything 9mm and up. The 10mm auto is about the most power that is useful on a Human target for defense, though. Anything more potent (such as .44 mag) won't incapacitate any faster and poses too much risk to bystanders.
Any cartridge producing between 350 and 800 ft/lbs is going to be effective enough without being excessively powerful (overpenetrating). What I mean is, over 350 they should expand a bullet and drive it deep enough, under 800 they aren't likely to push an expanded bullet out the back of the target with enough energy to kill another person.
In summary, with the proper bullet selection, any of the following cartridges (or similar unlisted ones) is an effective SD handgun round:
7.62x25mm
.327 Mag
9x19mm
9x21mm
.38 Super
.38 Spl +P
.357 Mag
.357 Sig
.40 S&W
.400 Cor-Bon
10mm Auto
.44 Spl.
.45 ACP
.45 Super
.460 Rowland
.45 Colt
All of these, with modern bullets, are capable of nearly doubling thier original diameter and penetrating at least 12" in calibrated gelatin. .32 H&R Mag, .380 ACP and standard pressure .38 Spl. teeter on the bottom end. I do regularly carry a .380, but with the understanding that it's not going to be as effective as a larger cartridge. This is offset by the extremely diminutive and light weight gun (P3AT) being able to be carried when larger guns are inconvenient or impossible.
I personally feel that anything smaller than .30 caliber or less (handguns) or that makes less power than the .380 is insufficient for SD. This includes .22 Rimfire, 5.7x28, .25 ACP, .32 ACP and a nuumber of other, less common cartridges.
On the other end, I feel that anything more potent than 10mm is too much of a liability. This includes .44 mag, .45 Win Mag, .454 Casull, .460 S&W, .480 Ruger, .50 AE, .500 S&W, etc. These powerhouses are best left for taking game or enjoying recoil and muzzle blast at the range.
YMMV
SwampFox Premium - Max Velocity Ammo
1 each 50 round box
357 Magnum
125gr Speer Gold Dot Bullets
New Starline Brass or Top Brass
Winchester or Remington large Pistol Primers
Hodgdon and/or Winchester Powder, Hand Weighed
1900fps 1000 ft/lbs energy@ Muzzle. From a S&W 5 inch barrel.
If you like the bullets but don't want max power we
can load them to your spec's, Just let me know.
max overall length 1.250" to 1.253"
Over 25 years experience loading ammo
Hahaha. 25 years experience loading ammo, and he list a max COAL that is less than the
CASE LENGTH (1.29")???
And sorry, but those numbers are pushing it from a carbine, let alone a revolver.
The only thing that guy has to sell is BS.