Well Hi There, T&B!

Yes you know I am a .357 Sig fanboy and I am bewildered that S&W chose not to chamber any 3rd gens in that hot round.

In my own experience, it is a recipe for incipient and eventual failure to start with a barrel proofed for a lower pressure cartridge, thin the chamber walls by reaming to accommodate the larger, high pressure cartridge, and then stick it in an aluminum frame admittedly designed as a compromise between weight and longevity.

When I tried it, even with Wolff's strongest recoil spring, that barrel left a mark where it hit that aluminum frame.

OTOH, if a shooter were to source a custom barrel, from a maker who understands metallurgy and high pressure chamber containment, and install it in a steel framed 3rd gen, then that would be an acceptable combination.

My own experience with .357 Sig barrels in steel frame 3rd gens has been quite satisfactory (as long as I run enough spring).

BTW, a 5" barreled .357 Sig semi-auto should have ballistics approaching that of the "king of the one-shot stops", the vaunted .357 Magnum out of a 4" revolver.

John