Does anyone know what calculation determines how much your weapon degrades with each strike? Higher-damage weapons seem to degrade faster, but not linearly...

That's only because higher-damage weapons usually weigh more, but not always. That's why it's not linear.

What I don't know is how much the weight and the strenght you hit (i.e. how long are you pressing the mouse button before you let go) affect to degration. I'd like to know the formula as well. Don't think it had anything to do with damage at all, just the weight...