I use the standard power-rib mainspring in my model 629... It has been in there for years.
I can tell you that I have never had a mis-fire due to a light primer strike, and the difference in smoothness between the power-rib mainspring and the factory main spring is really astounding to me.
When I get ready to smooth out a S&W for myself, all I do is change the mainspring to a standard rate power-rib mainspring, and while I'm in there, I use q-tips to clean every little nook and cranny inside the revolver. If I see an obvious burr, I smooth it out. I then reassemble the revolver using a good quality lubricant as I go. Others have marveled at the smoothness attained through these easy steps.
Regards,
Raven6