Numrich Corp seems to be sold out. Might try Midway or Jack First. Last resort would be E-bay, although I've been lucky enough to pick-up a couple of hammers & triggers on there. From the Numrich website it appears the same hammer fits all these models: SMITH & WESSON: 17-1, -2, -7, 17-4, 17-6, 18-4, 48, 48-1, 48-2, 48-4, 17, 17-5, 17-8, 18.
Good luck, hardcase60
Thanks for the replies ...I did try Numrich but they have nothing . Most of their stuff is used any way and I was looking & hoping for new . Jack First is out as well. I'll keep an eye on ebay I guess something will turn up sooner or later .