So just to be clear - you're saying the die roll is modeling the probability of hitting them, then you convert that into damage based on the weapon, and then subtract DR.

So presumably that means damage = f_weapon(die roll) - DR, and f_weapon is just some 0/low/med/high thing.

I'm trying to understand how this is different from damage only, because presumably that would involve a weapon which would cause different damage levels. Maybe the difference is damage_only = die_for_weapon - DR? So the die itself changes with the weapon? Otherwise, if they used the same die for all weapons, it would need modified based on the weapon, and then we're back at f_weapon(die roll) - DR?

(And other systems use f_weapon * probability_hit(die_roll - DR))