What is the true nature of karma? The more I study and meditate upon karma the more I am convinced that it is a physical thing and not a moral one.

The universe is a massive interweaving assemblage of gears and wheels and shafts and cogs. By doing this simple action (we'll call it "X") you create a rippling of reactions as a direct result. These are the primary reactions then secondary then tertiary and so on. 

Thus the momentum imparted from the original action resulted in countless other effects. And the momentum or propensity of the actions to continue in that general direction is in my opinion the true nature of karma. 

Not some altruistic ideology that frowns upon immoral actions and exacts a eventual penalty just for that reason. Now, granted, the ill effects on others from those type of negative actions may create its own karmic momentum. But so many see karma as some sort of cosmic police force and that just isnt the case. At least not as I see it.

Would someone agree or set me straight?
O! Bhikkhus, it is volition - cetana that I call Kamma, -cetanaham
  bhikkhave kammam vadami


Karma is always mental. But the consequences(Vipaaka) are both mental and physical.