That is true. It would be different for every bow. I would love to give you the scale on the x and y, but I really don't know. OHbowhntr gave some great details that should help.

Alright, that is news to me. I believe you though. Now I just need to decide how much speed I need to sacrifice. I'm thinking that I want to shoot at about 300 FPS. You seemed to think that a 560 grain arrow would do that at 73#.

If I am shooting a 560 grain arrow, I would like to have the 185 grain Magnus Snuffers on there. What is the best shaft that can handle that head? I'm looking for 12%-15% FOC.

Everyone will have diffiering opinions on best shaft. Here is mine: Right now I have a Carbon Tech Whitetail XP shaft 65/80 (.300 spine) at 30" with a 200/220 gr Muzzy Phantom SS with a 4 feather fletch and it weighs 533gr with a 17% FOC.

http://www.carbontecharrows.com/

I buy the shafts here:
http://www.lancasterarchery.com/shop/product_info.php?cPath=38_79_65_86&products_id =1571

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Alright, that is news to me. I believe you though. Now I just need to decide how much speed I need to sacrifice. I'm thinking that I want to shoot at about 300 FPS. You seemed to think that a 560 grain arrow would do that at 73#.

If I am shooting a 560 grain arrow, I would like to have the 185 grain Magnus Snuffers on there. What is the best shaft that can handle that head? I'm looking for 12%-15% FOC.
[/quote]

Wow! I didn't run that on OT2 (I'm at work, lunch break) but a 560 grain arrow at 300 fps! You could shoot an armored truck with that! I did mess around with OT2 the other day, wondering about the exact same question you asked. I found that the momentum does not top out in that program. I'm not convinced that is accurate. A compound bowwill deliver a constant amount of force via the string to the arrow (at a given draw weight). According to Newton's Second Law, increasing the mass of the arrow will decrease the acceleration of the arrow, which in turn will decrease the velocity of the arrow, which will in turn decrease the momentum of the arrow. Somewhere in that relationship there must be a point of deminishing returns (this must betrue as at a high enough arrow mass, the acceleration of the arrow with the a constant force will be zero)-in other words,an arrow that will deliver the maximum amount ofmomentumas evidenced by the vertex of the parabola(the y-coordinate of the vertex of the parabola you posted earlier) as a function of the mass of the arrow (the x-coordiante of the vertex of the parabola). But I'm damned if I know how to come up with the vertex of that parabola!

I would personally use the Easton Axis FMJ for maximum penetration. The small diameter slippery shafts will penetrate like a much heavier arrow, and you won't give up as much trajectory. Use 125 grain heads to maximize FOC - a NAP Hellrazer would be good, as well the heavier Slick Trick, Magnus Stinger, or G5 Montec. Or even some of the heavier Muzzy Phantom heads.

Not trying to argue here but if you can get 300fps with a 560 grain arrow with an 82nd at 73 pounds Iwill drive to your house and kiss your rear end.

A 560 grain arrow should be clocking at about 280ish with a 30 inch draw and 73 pounds.

A 480 - 490 grain arrow will be hovering around the 300fps mark.

My 60# 28" draw 82nd produces more KE with a 400 grain arrow than it does a 500 grain arrow. That was computed from actual performance not some software

Dan

I'm just saying what OT2 quoted it as an "expected" speed. I thought it seemed a little FAST as well, but that I believe is the downside of OT2, I'm not 100% sure all of their calculations are correct. It puts my Trykon XL at 286fps as I have it set-up, but I've only gotten as fast as 276-277 blowing through a chrono. So I'm sure that's a HIGH guestimation. But even at 280, that's SMOKING for a LOG!!!!

Dang right!An arrow that heavy at thatspeedcould blow through an elephant.

I have found Archers Advantage to be more accurate than ot2 and it says 291 BUT,bowtech gives the ibo from 342 to 350 and I believeAA uses the top end.If the bow only hits the low end,that puts it at or around 283 fps.


That should get it done regardless.