AFAIK, the 63 is all steel. The reason it is lighter than your 617 is because it's a J-frame. My J-frame model 60 weighs only 25oz. Although it's a shame, IMO, that S&W chooses not to produce a 3" or 4" 63 at this time, I think the current 5" model is just peachy. A few years back, I bought a 5" Taurus model 94 - which is dimensionally, almost the same as the 5" 63. I find it to be a swell little field gun for small game and varmints, and pretty darn good for informal target shooting.
I would expect (and reports I've read confirm it) that the new S&W 63 is every bit as dandy as my T94 - if not better. I haven't handled one yet (don't feel the need), but from what I've seen and read, the sights and the trigger are a bit better than those on my 94. One gunwriter even went as far as to claim the 63 is a better gun for most people (not into formal target shooting) than the 617 - and I would have to agree.
