9x19,
I used the Trapper kit once for a J frame, and it worked fine,with the light rebound and the reduced tension main spring. There were no pound ratings on the springs though, just "light"and "medium". Do you know how many pound the Trapper rebound springs are, for the S&W ? I like light springs in my guns, and so far found the Wolf 11lb. to be the lightest available.
MR.G