RE: Arrow penetration vs. weight
I'm also wondering about this diameter thing. If the material used to test penetration is something that also imparts friction on the arrow shaft as it passes through, then a smaller diameter arrow is going to have a distinct advantage. Other than the hide, I don't see a flesh and blood deer's body asputting much friction on the arrow shaft. In fact, blood and other body fluids might tend to lubricate the arrow shaft a little.