I don't know enough about fluid mechanics, but don't blunt-nosed teardrop shapes have the best BC when they're subsonic?
No. BC is BC weather or not it's above or below the sound barrier. Drag is Drag. Blunt nosed bullets do have one advantage... which is why slippery pointy boat tails are not always the best choice. Tissue disruption. That wider ogive when it hits - disrupts more tissue. It's not a stabbing cut like a pointy bullet. It's a blunt force trauma that penetrates.
Look at the bow of a ship. Say, a sleek sail boat. It cuts the water with ease and glides through leaving a wake like an arrow-head. That wake is the water being pushed away. So the boat, with its sharp lines, loses less energy, so it needs less energy to move through the water.
Now look at the bow of an Ice Breaker or a Ferry. Wide and blunt. Look at the water piling up against the bow. Look at the wakes. These ships really have to push a lot of water out of the way.
Air behaves the same way. Air is essentially, a thin fluid. It moves the same. Get a cigarette and blow some smoke. And pass your hand through it flat and edged and look at how it behaves. Go out to a lake and take a cannoe paddle. Run it through the water the same way... flat and on edge and look at how the water moves. The same.
Now, as you know... tissue is like fluid too.
Now with tissue you get other neat things. Bone shards, tendons, blood, etc.
The .300 Whisper doesn't depend on shock like the 556 does. It uses good old fashioned penetration. Momentum and large permanent wound channels.