Mehul,
The Nimrod (boxlock) action is quite different from the usual A&D design on which many DR's are built.
One big difference is that the mainsprings are connected to the tumblers using a connecting rod which gives a compound leverage to the system.
This system provides MAXIMUM spring tension and energy at the point where the striker hits the primer, but also produces MINIMUM spring tension when the tumbler is in the fully cocked position. This creates a low loading on the trigger sears, which allows a very light yet safe trigger pull weight.
The trigger sears are also positioned much further from the tumblers pivot point than on most other boxlock designs, and this also adds to a lighter trigger pull while still retaining a safe sear engagement.

The Nimrod is truely an innovative and fascinating design!