The Model 19 frame is also slightly longer just beneath the ejector rod,
If you look closely in this picture of Models 15,14 and 19 (L to R) it is easier to see.


The marriage of the K frame to the .357 was brilliant but imagine the shock when they announced their intention adapt the J frame to .357 ,
Probably a few skeptics said it could not be done.

The Model 19 frame shape (right) is actually more like the Model 14 (center) with its square frame shoulders and wide rib barrel than the tapered barrel Model 15 (left) but if a Model 19 barrel was installed on a Model 14 it would overhang the frame slightly.




Here is one with a Pre Model 10 (far right) for comparison as well.


Interesting stuff..