Memory is sketchy so I might get a minor detail incorrect, but...
The recommendation about using .38's for regular practice and .357's for "serious social work only" as they called it was long known about the M19.
What brought about the eventual introduction of the L frame was the introduction of the hot 125 grain loadings. These ate away at the forcing cone of the Model 19's and eventually produced cracks (
IIRC).
The Model 19 in good shape is a great revolver. I had one in 4" around 1969 or 70 and sent it back to Smith for a 6" barrel and their then relatively new red ramp/white outline sights. It was a great revolver, very accurate and of course the action was like a jeweled Swiss watch.
But I'm a bit leery of used ones nowadays since you don't know the history of what they'be been fed for the last few decades. If one is in good shape then it's in good shape, but unless you really knew what you were doing and how to evaluate wear you could get stuck with one on the verge of getting worn out.
Speaking of L frames and worn out revolvers, I got a no dash 586 6" in 1981 and shot that thing so much I finally had to send it back to Smith sometime in the late 90's for an overhaul. It's still a heck of an accurate revolver although it doesn't get shot anymore since I got a 6" half lug stainless GP-100.
