Hmmm, not what I've seen in my testing nor the gel tests that I have seen around the net. Can more velocity cause more penetration from over expansion (petals folding back around the core of the bullet)? Sure. Most times velocity hinders penetration because of increased deformation of the projectile and the increase of resistance from retarding forces. The difference I've witnessed between the calibers was much more pronounced in the way of destruction, if you will, not penetration. Now when you say "over penetration' do you mean it just simply penetrated more than the others? It actually takes a lot of penetration to really count as over penetration.