Andrew R Stewart 

Photos?

Ben- I agree with the introduction of indexing the shifting is often more abusive. Although I think it's the teeth profiling and lift pins that are more to blame as they aid the ability to get away with loaded shifting (and sometimes not even know it). For the first dozen or so years of my wrenching the incident of chain side plate pull off failures was pretty small and often helped by poor technique when pressing the pin (remember back then one was to reuse the OEM pin) back in. But by the midish 1980s the chain breakage numbers grew a lot as indexing was starting to take over the market but the supply chain (pun) still had pre peening chain pins designs on the shelves. The next wave (sort of) of chain failures was many not assembling their Shimano chains with their specific reassembly pin (that compensates for the bigger hole that the peened end pin punches through the side plate on removal) or doing so properly. I think this is where SRAM, KMC, et al, found their footing with their connecting link proving to be less likely to be misused. Andy