[Buffalobob]

You might want to consider that lead is a lot denser than copper and that momentum is the product of mass and velocity.


This then leads to the interesting possibility that a Nosler partition that has expanded down to the partition is heavier than a piece of solid copper and will penetrate further. Of course there is the energy of deformation loss and then there is the question of frontal area of a Nosler so it might not work out so simply.