Arthur,you have hit on one of the points I have tried to make in this discussion in the past.At what point does the stored energy start to get wasted.Is it a good idea to put an 800 gr arrow on a 40# bow with a 26" draw.I really think that would be a waste.Where is the line drawn.Really with your setup I wouldn't call a 600 gr arrow all that heavy but for me it is heavy.I really think the arrow manufacturer's have it pretty well set on the heavy end.You need to be carefull on the light end.You can get too light but at what pooint are we too heavy.At what point are we too light,I think the AMO has set it nicely with their minimum chart.
We all are starting to agree that carbon penetrates better than aluminum.So that really takes the notion that ke,momentum or even speed is better for penetration out of the mix.
It boils down to how well an arrow is built or how well balanced it is or what material it is made of.I know from testing that my Nitro Stinger at 360 gr penetrate better than a 450 gr aluminum of the same diameter.The aluminum has more ke and momentum but DOES NOT penetrate better.This says to me that the arrow determines penetration and not any number that we come up with on paper.Yes the numbers are good guide lines and if given 2 arrows that are identical in everything except weight then the heavy would win out but that is the only time you can go by the numbers,unless of course 1 is shot from a tuned bow and the other 1 is not tuned to the same bow.Then we tip one with a 2" broadhead with 4 blades and the other 1 with a 2 blade that is 1" in diameter.The smaller head will win but the numbers will be the same.
You can also take a 700 gr arrow and get the foc down to 5% and it going to stop in it's tracks when it hits bone,regardless of what the momentum or ke is.I did this on a piece of wood with a stinger filled with water and it stopped dead in it's tracks but jacking the foc up to 10% made a huge difference.You can get by with less foc if you have high ke levels but if you go too low you are stuck.If you have low ke,then foc becomes of greater importance.
The fletching is a huge part.Put a 5" extreme helical feather on an arrow and you have in affect put a parachute on the back of the arrow(to coin a phrase that Arthur once used).In affect reducing the amount of energy that will be used at the target.Use a 3" slightly offset fletching as I do and you have increased the downrange energy.
The variables are way to endless to put all the importance on a couple numbers,yes they are a good guideline but that is it,a guideline.I could go on and on but I think I have already.
Just one more thing for you Arthur.
I built Kinetic II's for both our bows using what you give on your bow.
My Kinetic II would weigh 465 gr and produce 60.9 ft/lb ke at the bow.At 30 yards I produce 55.5 ft/lb ke.243 fps at o yards and 232 fps atr 30 yards.
You would use the Kinetic II 300's weighing in at 555 gr.You would produce 60.8 ft/lb at the bow and 53.5 ft/lb ke at 30 yards.222 fps at the bow and 208 fps at 30 yards.
You lose 2 more ft/lb ke than I do.
I did use the same fletch length on both arrows but that would make even more of a change.The reason you lose more than I is due to the length of the arrows.Mine are 27" and your are 33".I believe I had your setup right but even if it is not exact you can see how much difference there is in 2 bows and how much little things like arrow length play into the penetration issue.
Very interesting. <img src=icon_smile_tongue.gif border=0 align=middle>
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