I have been assuming - prolly wrongly - that the .357 Ti cylinders on Midway will fit a 442 ... at least per the Midway reviews. Still available with a 4-month old 642 review.
Smith & Wesson Cylinder Assembly S&W J-Frame 357 Mag - MPN: 229390000
Smith & Wesson Cylinder Assembly S&W J-Frame 357 Mag - MPN: 229390000