I may be thinking incorrectly but I don't see how this test couold be possible. Using the same arrow diameter and foc can be accomplished , but increasing the weight is not. That would entail jumping a cuople sizes up of the same arrow (i.e. Beman 400 to 300 to increase the weight enough to get 100 grs more) and keeping the diameter and foc the same by using the same fletching,tip,and nock, but the spine would be way off. Even if you could increase the weight of the shaft itself the spine changes.
You would have to get an arrow manufacturer to make 2 arrows w/ the same spine that were 100+ different in weight to run a test like this.

So I think we can conclude that spine and foc as well as mass and speed contribute to penetration. They are all functions in and of themselves. The variables(I don't believe) can't be eliminated.
[/quote]

Thank you.

Does anyone know the record for # of pages in a thread?