I don't think I'd worry too much about hurting a K frame snubby with full power loads. I don't think you'll shoot that many full power loads through it.
I have a 3" 66 and it is one of my favorites, but I only fire a few full power loads through it during each range session. They're just not that much fun with full power loads.
FWIW I shoot mostly 140s for all of my full power 357 loads. Cast 158 or 125 at a mid level (357) if fun and works for most of my needs..

Ernie

George Washington - �Labour to keep alive in your breast that little spark of celestial fire,�conscience.�

God save the Republic