I had one come in. The young man was ranting about how heavy the trigger pull was (okay, an old man about 80 years old). I advised him that most people will not lighten the trigger of a derringer for safety reasons. Well, someone cut the main spring for the guy. It supposedly lightened the trigger, but it also developed light hammer hits. To make the story short, I ended up with the gun after doing a transfer on a .380 he purchased. I got a new main spring from Cobra and installed it. Live fire tests had light hits on the primers (not enough to fire, but I could see where they were hitting). I think the problem could be the main spring, but could something else be hindering the firing pins?