The manual says screwing the adjustment screw too tight can stop the trigger catching the notch of it's cam surface, so that could be your problem with it not "setting".
Another potential fishhook...
Type: Posts; User: Cigar
The manual says screwing the adjustment screw too tight can stop the trigger catching the notch of it's cam surface, so that could be your problem with it not "setting".
Another potential fishhook...
How exactly have you been adjusting the set trigger?