It's all about the ammo availability...
It's a damned good question, especially since there's a number of people who want NAA to scale up the BW into a four or five shot .32Mag, retaining the SA action and spur trigger.
CorBon *was* going to do a super-hot 60grain JHP in .32Mag, basically using a good .32ACP projectile and making it go faster. That sucker would almost certainly beat out just about any possible .22Mag load in any barrel under 8" or so.
But that CorBon wasn't selling, so they killed it.
You could handload something similar mebbe.
The only other really hot .32Mag defense load I'm aware of is the MagSafe Defender. If I recall, that's a 35grain load doing better than 1200fps from even a short tube. Not certain though, I'd want to look at the specs.
Now, all that aside, the Federal lead hollowpoint .32Mag is, what 90 grains or so, doing about 800fps from a snubbie? That's still more energy than the CCI MaxiMag +V from the 4" tube. If you put that on target, no guarantee it'll expand but it WILL penetrate skull, which to me is the absolute minimum requirement for a mousegun load. So even with that minimum-level .32Mag, it's more effective than the hot CCI .22Mags. Not much more. Faster reloads though
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Yep. .32Mag wins. Mind you, it's a bulkier gun to conceal - the MiniMaster may be a hair longer but in every other direction, it just plain evaporates under minimal concealment.
I'd rather have five good .38+Ps than six .32Mags. If really good .32Mag fodder starts shipping, or I was a reloader, I might reconsider.
Last point: Taurus sells a J-class snubbie in 8-shot .22Mag, with a 2" or 4" barrel. With that many rounds on tap, and per-shot performance so close to .32Mag, that puppy bears considering for some needs, especially those who can't deal with .38 recoil due to injury/arthritis.