I have an FMK 9C1 DAO gun. Dry-firing has a very light (but still long) trigger. With a snap-cap, the trigger is still light (and long). However, with a real 9mm round, the trigger got much heavier to the point that it seems not to want to release the firing pin. I really have to pull very hard. Why the differences among the three types of trigger scenarios, and how can I lighten the trigger with a real 9mm round? Thank you.

