You cannot go wrong with a 48 or 18.
JT-AR-MG42, I find it hard to tell whether you're talking about .22WMR or .22LR from sentence to sentence in your post.
The factory .22WMR / .22Mag Smiths are the Models 51, 351PD, 650, and 651 (J frame), and the Models 48 and 648 (K frame).
The Model 18 was normally 22LR only. If you've seen one in .22WMR, it's not standard production, or it's (more likely) a gunsmith conversion inspired by the relative scarcity of M48s with 4" barrels.
One interesting thing about older .22WMR S&Ws is that the barrels had a non-standard rollmark that read ".22 M.R.F. CTG." for .22 M