Another option is to look for a 431 (hammer) 432 (hammerless) or even 331 (hammer) or 332 (hammerless). The 331/332 is partially Titanium and a lot lighter than the 631. I posted a link to my earlier thread about a 631. Bought it from a new member, he had one S&W and only one post. The deal went great and my kids are fighting over it.
S&W Model 631