Well that is your opinion, and your welcome to it, but it is really just that, your opinion. There are many more factors that go into the penitration issue other than flat out Ke at a specific range.

And the grain/lb you decide to shoot really depends on your particular set up. 9 grn/ lb for me is way to heavy, but I don't have a real efficient bow and only draw 26 inches. The equivilant for my bow is -1.7 grns/lb.

Ke, really only measures the amount of knockdown power something has at a given range. Some other things that effect penitration are arrow dia., arrow stiffness, resistance of the target, and head type. My bow will actually get better penitration on a 3-d target with a lighter arrow than a heavier one. The heavier one hits the target harder, but does not really penitrate deeper.

You do make a good point and I mostly agree with you. Using an extremely light arrow may not be your best bet, but then neither would a real heavy arrow. You need to find what works best with your bow. A happy medium between decent speed and efficient Ke.

I will tell you this though, and it actaully agrees with your above statement. My bow likes a heavier arrow as far as the amount of energy it will devolop. I went to a shop and chronoed some different arrows at different draw weights and then came home and entered the data into the Archer Program. What I found is my Perfomance factor goes up with the heavier arrow. I only got 183 fps out of a 456 grn arrow at 42 lbs. But when I compared it to a 312 grn arrow moving at 214 fps the performance factor was way higher. Like 1.4 for the heavier arrow, vrs 1.2 something for the lighter arrow.

Keep in mind that does not mean the heavier the arrow, the better it will work. If you go to extremes in either direction performance will suffer. Just because a calculator or mathmatical equation says a heavier arrow will hit harder does not mean you will get that sort of performance out of your bow. You can get to a point were the arrow is too heavy for the bow to use it effectively and your performance will actually start to decrease. The ballistics formulas do not take into account for that. The only way to really know is shoot that weight of an arrow out of your bow and record the speed, then compare it with other arrows.

With that said, I feel confident that my bow with 30 some ft/lbs of KE at 20 yards will zip thru a deer with the right head, as long as I didn't hit the shoulder. To say that someone shooting a faster bow that gets 60lbs of KE with a 300 grn arrow can't do the same thing is a bit rediculous. I am not saying that the same arrow at 400 grns or so would not work better, but at 20 yards it probably does not matter much.

Those are my opinions on the subject anyway.

Paul