Hey RS, I think you have them reversed. SR-77 is tougher and SR-101 is stronger.
Tougher means softer steel which equates to being able to take more bending, prying, etc. Stronger means more or less harder steel which equates to better edge holding but more brittle (hence, not as tough). Make sense? <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

It makes sense if you think about what their parent steels are used for...S7 is a spring steel used for making coil springs, etc. and I believe 52100 is a steel used for making ball bearings. Hope this helps. I'm sure someone will correct me if I have gotten anything wrong. <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" />