BC. You are right on that, most any good bullets will not lack penetration on deer size game. Therefore the velocity and shock effect is what you want. I really like the Partition and also the 300 grain Hornady HP. For bigger game like moose, you can't beat the 350 grain Hornady RN. Good penetration but also fair expansion. I have taken some really big Black Bears with that bullet from the Marlin. If I recall, I was getting about 1900 fps with that load.