Any corrosion on the cable ends?
I always use heavy gauge wire, and sealed ends on my battery cables. I've been told that the factory wiring on the starter solenoid is weak. And that you should upgrade to a heavy duty relay setup. I plan on doing it to mine in the near future. I get the famous click from time to time. And I installed new starter plunger contacts, and it still does it. I have a rather large Marlin Spike that is heavy enough to whack the starter.
