I purchased a 617 at a show a couple of years ago. Someone had obviously worked on the action because the trigger was lighter than on any of my other revolvers. My pleasure at the incredibly light and smooth action turned quickly to displeasure when I discovered that about one out of five rounds wouldn't fire in double action (single action was ok). So, I replaced the mainspring with a slightly heavier spring and it's been trouble-free ever since. Afterwards I spoke to someone at Smith who told me that they deliberately put in slightly heavier triggers than in their other K-L revolvers due to the inconsistency of .22 primers.