I believe I said this not Arthur, I think Arthur shoots heavier arrows than that. When I did this test with MY bow and MY set up it showed I had a maximum efficiency at around 450 grns. Every set up will be slightly different.

And my tests had nothing to do with performance on game. They were simply measuring the amount of penetration (depth) I could get with different arrows in a consistent medium. The problem with any of these tests into a medium like foam or any other target is that the thing is designed to stop an arrow by use of friction. You can't quantify things and say that if I shot an arrow with X amount of KE and momentum I would get this amount of penetration. And if I doubled that figure I would get twice the penetration. It won't work that way, I tried.

I really wanted to build something that would measure the amount of force that the arrow had when it struck something.

What I did notice is that there is a definite difference between light arrows and heavier arrows out of my bow. And I don't need to measure it to know it. When I was doing some tests shooting at a 3-D target you could hear and see the difference between the two arrows at 20 and 30 yards. The heavier arrows hit the target much harder and actually rocked it after the shot. The lighter arrows (300-350 grns) didn't hit as hard or move the target. This tells me that the heavier arrows carried more energy to the target for sure.

That being said I have seen a 350 grn arrow moving in the low 200 fps range with a good sharp head zip right though a deer and stick in the ground from 20 yards. And this was from a bow with 50 lbs of draw weight and 26 inches of draw. There are an awful lot of variables to how a particular arrow will penetrate in live game.

I will be honest, I haven't read DR Ashby's report, I already know what works for me and I don't plan on hunting cape buffalo or elephants. I might read it just for the heck of it when I have time though.

Paul