The Model 19 is legendary and Bill Jordan was the "father" of the K-frame .357.

Bill Jordan and S&W acknowledge that the K-frame .357's like the 19 were designed as LE duty guns, to be lighter in the holster and easier handling, while still allowing LEO's to use .357's for duty. They were never designed for a steady diet of .357. In the 70's and 80's PD's reported that 110-130 gr. .357's were loosening up their K-frame .357's, as well as cracking forcing cones and excessively flame cutting top straps. PD's started training with their duty ammo, rather than .38's.

I believe that occasional use of 158 gr. .357's will not hurt a k-frame .357, but the light bullet .357's are not recommended in any amount other than a token amount of test firing.