Some stainless models seem to follow a logical pattern:
M629 is the stainless version of the M29
M657 is the stainless version of the M57, and so on.
Then you come to the M610. No, it's NOT a stainless M10 (the stainless M10 is the M64 … oh well, it starts with a "6").
The M610 has no antecedent. It is a stainless revolver chambered for the 10 mm auto cartridge.
All we can say is S&W was consistently inconsistent.
