The 10mm has a harder knock down power because I have killed many large animals (deer) with both. I have ACTUALLY seen the effect of both rounds with field dressing and butchering the animals afterward. Real field experience trumps any figures in a book because deer can't read. Even most all professional hunters put the 357magnum in a marginal category for hunting deer and reomend a 10mm or 41magnum as a better choice. The 10mm kills faster. Nuff said.