Rob, mon ami, you bring about another good point. I was thinking about this topic today, and I thought of this....tell me what you think.

Ok, let's take a rocket hammerhead, just to use in this scenario. The blades fold up along the ferrule, and sweep back when deployed. Arrow is launched, tip strikes deer in the ribs. Point of the head enters deer and the tip of the blades enter next. At this moment, we have an entry hole the size of the tip, right? Ok....but the blades sweep BACK, toward the entry hole, right? When fully deployed, they actually extend behind the BH, thus making the entry hole the size of the blades.....Make sense, or am I all washed up here??