Bottleneck revolver loads are not known for reliable performance as they can tie up the cylinder.

Some report the .32 Mag does well with max loads.

.30 Carbine in a pistol also has a good varmint rep except that the Ruger was a boat anchor and the AMT was known for operating as a reliable single shot...........

I failed to mention what might be as good as the 7.62x25, the 5.7 FN PDW round in the FN FiveseveN pistol. There is a cult following for that one and its ballistics look very good for varmints. I have no experience with it as I have my Tokarevs and the price of gun & ammo has scared me off. But I'd like one at least to try it out.