I would call a running shot, or any shot where one has to penetrate through a bunch of deer to reach vitals a low % shot.
I suspect what you're seeing is "limited sampling" affecting your perception of what works and what doesn't. Shoot enough deer, and you'll see all sorts of things.
When it comes down to it, there is basically no difference in the killing power of our most popular big game cartridges, especially on deer.
