As the owner of several modern Smith revolvers--with the lock--I had always been skeptical about the frequently expressed concern that the lock could spontaneously engage....until today that is. I set up a target and started shooting with my model 632. On what should have been the 5th shot the gun locked up. I've read that this was most likely to occur when shooting heavy loads in light revolvers. I was shooting very light handloads--1.5gr Bullseye, 90 grain cast bullet in .32 acp cases. Furthermore, I've shot this gun very little since buying it new and always with light or moderate loads. I've never used .327 magnums--.32 long, .32 HandR, .32acp only.
This incident has caused me to seriously rethink some things. My usual carry guns have been a 642 or a 432--both with locks. I will be having those removed and in the meantime will go back to carrying my 70's vintage Chief's Special.
Lock failure--IT CAN AND DOES HAPPEN!