Weight is actually why I wasn't interested in the 9mm LCR; I dont want to exceed 16oz loaded for pocket carry, which the M&P 340 just squeeks by with. And all the .38 +p loads seem marginal in realiability, leaving only the 'short barrel' optimized .357s for carry. Being able to just use regular 9mm +p JHP that I stock in bulk would be wonderful
My ideal fantasy land is that S&W designs a 9mm 340 ultralight with a shorter 9mm length cylinder/frame. And then uses that shorter cylinder to offer a longer barrel while keeping it J-frame OAL. IE so like a short cylinder with 2.25-2.5" barrel.
Since the revolver cylinder is the main weight generator, this could also shave weight down to the ~12oz zone.
Terrible sketch of the concept.