redleg:
I detail stripped mine more times than I can count. I think the spring that pushes the sear up weakens during use, this will cause the firing pin to slip forward over the sear during cycling, instead of catching on it and being "cocked." This reults in the trigger doing nothing.
If you bend the sear spring a little using only your fingers, such that the upward force on the sear is increased, it might start working.
I don't know if this is the problem you're having or if you're interested in amateur gunsmith advice, your liability situation may prohibit you from implementing advice from "some guy on the internet." I can provide more info if you want.