This whole "argument" goes much deeper than the physical diameter of the bullet. Bullet diameter has little to do with it. Its the whole velocity, engery, taylor knock out factor blah blah blah. Ok maybe not the TKF.
Thats like comparing a 12 guage slug to a Barret 50 cal. A 12 guage will shoot a slug that is approx. 70 cal. And obviously a 50 cal is 50 cal. Your saying the 12 guage slug is way more powerful? You smell what I'm cookin?