Even after a lot of challenge, I'm still of the mind that there is a sliding scale of caliber to appropriate size and weight. In snubs, .38 special feels alright and +P is as much pop as I'd ever want in such a small package. Other posters are right that not only do you punish yourself with the magnum but you are nowhere near getting all the bang for your buck in that barrel length. Honestly, I prefer six-shot .32 H&R magnum with the right bullets in a snub-nosed revolver.
As you increase the size of your piece, you increase both ballistic performance and comfortable choice of caliber.