You can find the weights and measurements on the Ruger website.
I love my SP101, and carry it every day. Right now I am over at a friend's house, and it is right next to be bed playing HD gun for the night.
Mine is in .357 mag with a 3"bbl. I can tell you right now, it's not as tough as a large frame revolver, but for a small guy, this thing is tough as nails. I have shot everything from mouse-fart .38's, all the way to firebreathing-dragon killing-butt stomping-full house magnums through it, and it handles them all gracefully and asks for more. Like any smaller gun, recoil can be stout with the crazy loads, but so much better than the super light weight guns.