In 357 Magnum, magnum loads with bullets lighter than 140 grains will wear away and put more stress on the forcing cone than heavier bullets. The new Model 19 and 66 have a thicker forcing cone, so it should hold up better than the older versions.

With 158 grain bullets, I expect your wrist will wear out before the forcing gives out. The Model 19 was originally intended to be used mostly with 38 Special loads and occasionally with 357 Magnum loads. It is harder to control with Magnum loads than the heavier Models 27, 28, 586/686.