IIRC, the problem with the K frame, particularly the M-19, came about when the light weight, high velocity loading was in vogue. The smaller bullets, particularly the 125gr, wore the forcing cone and also lead to some stretching of the front strap. TTBOMK, there has never been an issue with the heavier bullets.
The M-19, though, was a compromise. Many duty officers found the larger N frame guns, the 357 and later the M-27 and M-28s too heavy for constant wear. S&W was asked to design a gun that would shoot 357Magnum loads as duty use, 38 Special for pratice, that would be lighter and point as well or better than the N frames. The result was the M-19.
I would hate to guess how many rounds of 357Mag have gone throuogh my M-19s. It's been a bunch though. I tend to select the heavier bullets though with 158 being a favorite. So far, they have held up and despite the popular wisdom, decades and decades later they are still going strong. The M-19, in addition to being a (IMHO) beautiful gun, is also extremely well balanced. I love my N frames but the M-19 is perhaps even more fun to shoot.