Chris gets right to the reason I switched from a .38 Special Model 442 to a .32 H&R Magnum Model 432 back in 2005 and haven't ever thought about switching back.
.38 Special does not expand reliably from a 2" barrel in any loading. The only way you'll see expansion from a J-frame is to step up to .357, but .357 Magnum out of an Airweight is punishing. Followup shots are slow, and that's the sort of recoil that adversely affects accuracy.
Look at Chris's posted times in the 5x5x5 drill for the different calibers. There's something like a full second's difference between .32 H&R and .357 Mag. I know the guy reading this who carries one of those flyweight Smith .357's with a frame made out of Riboflavin alloy or whatever is like "Well, I shoot magnums just as good as regular .38's." No. No you don't. Video with a timer or GTFO.
Since all pistol bullets do is poke holes, we need the holes to go as deep as necessary to poke holes in important stuff inside the bad guy, without poking holes in important stuff on the far side of the bad guy.
This is why I have Federal 95gr LSWC in my 432PD; it's reliably found in the denim on the far side of the jello block, just like 148gr .38 Special wadcutters are, and it recoils about the same in an Airweight snubbie, and I get six of them instead of five; a 20% capacity advantage.
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