The new SP101 .357 Magnum with adjustable sights is a 4" barrel. The 60-15 is a 3".
I have two of the pre-IL 60-10s and they are my favorite backpacking, fishing, canoeing, anything around water gun. I have shot them side by side with .357s from 3" Model 65 K-frame and there is very little difference....
Bob