I have been having this problem with my cylinder skipping.
I bought my 500 used from a good friend who bought it new.
The first time I took it out, we shot only about 20 rounds or so when it started. I would load all 5 and pull the hammer back every time before firing, and at least once sometimes twice it would dry fire on a spent round before all 5 were shot. This happens after firing 2-3 loads, then almost every load it will skip at least once.
Anyone have any feed back?