I believe that you are saying that the small dent is to the primer. Your problem is most likely the retracting firing pin. I bought one El Patron, and had lots of problems with failure to fire. I believe that I was pulling the trigger until the hammer began to fall, then releasing the trigger. If I fired and intentionally pulled the trigger back as far as I could, I didn't have the problem. But I couldn't seem to do that when shooting a stage. The problem, I believe, is the firing pin has moved back from it's most forward position at contact with the primer, thus lightly denting the primer.
I bought the 4 click hammer and trigger from VTI for the Cattleman, and installed both and have no problems. I believe that someone in another post said that Long Hunter and others had a kit including hammer and trigger that was less expensive than VTI.