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Discussion Starter #1
Mathews Switchback XT 70 lbs. 27" draw

Carbon Express Maxima 311 grains


298 fps. 59.85 ft/lbs of kinetic energy



Old setup

same bow
400 grain arrow

256fps

60.1 ft/lbs of kinetic energy.


I realize I am running a light arrow but I have the same amount of energy as I did with the heavy arrow? Why is that? It goes against evrything people have told me??
 

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Could it be the almost 42 fps of speed you gained???????

You gained KE, but most likely lost alot of momentum.
 

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Trollinus Maximus.
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Could it be the almost 42 fps of speed you gained???????

You gained KE, but most likely lost alot of momentum.
+2 :darkbeer:
 

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Discussion Starter #5
How do you gain energy and loose momentum? I thought it was the same thing??


I am being serious too I reall y dont understand..


Should I be ok with Grim Reaper razortip 85 grain?? for passthroughs??
 

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It can be pretty confusing. I think if you have an opportunity to check speeds on a lot of bows, you'll find that the KE numbers are pretty much the same. Most bows will net a bit more with as that arrow weight goes up, but not by much.

Momentum is almost as confusing, as the numbers are small numbers to compare.

Myself, I don't notice a lot of difference on deer size critters with shafts running from 320gr-500gr from a 60lb bow with most broadheads. I've used a couple larger expandables that might not be the best on the lightest arrows, but with a fixed blade head, most seem pretty much the same for penetration.
 

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How do you gain energy and loose momentum? I thought it was the same thing??


I am being serious too I reall y dont understand..


Should I be ok with Grim Reaper razortip 85 grain?? for passthroughs??

HD-think of it like this, you use a 16lb. bowling ball and throw it down the lane as hard as you can-it moves relatively average speed it hits the lead pin and just blows through the pins. It does not slow down until it hits an immovable object-the back wall. Now you switch to a 11 lb ball and all other things are equal. you throw the lighter ball with the same amount of force but it travels much faster down the lane. However, as soon as it hits the lead pin it deflects and immediatly begins to slow down because it does not have the same momentum as the heavier ball.
 

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Fat Jesus
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If that's 311 grs for a finished arrow weight including broadhead your WAY under IBO weight at 70lbs. It should weigh in atleast 350grs finished.
You'd be better off shooting the heavier setup, and your bow's limbs & strings will thank you too.
 

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Dad its pretty simple...it takes longer ( more yardage) for a heavier arrow to slow down than it does for a light arrow even though they both have nearly the same K/E...think of it as getting hit with a ball bat ( heavy arrow) and compare that with getting hit with a whiffle ball bat...the whiffle ball bat is lighter and can be swung faster but doesnt hit as hard...You have more momemtum ( felt pain ) with the regular ball bat....JMO
 

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HD-think of it like this, you use a 16lb. bowling ball and throw it down the lane as hard as you can-it moves relatively average speed it hits the lead pin and just blows through the pins. It does not slow down until it hits an immovable object-the back wall. Now you switch to a 11 lb ball and all other things are equal. you throw the lighter ball with the same amount of force but it travels much faster down the lane. However, as soon as it hits the lead pin it deflects and immediatly begins to slow down because it does not have the same momentum as the heavier ball.
Spot on and very well said.

Now for the weight of your arrow as someone else said...if you wanna shoot that bow long you better bump the arrow weight up about 40gr.
 

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MD
I found the same thing and and sticking with the heavier arrow due to the momentum which was explained well in the bowling ball and bat comparison.
My Z32
28.5 draw 60 lbs
390 grain arrow 264fps 60 ke
300 grain arrow 298fps 60ke

sounds cooler to shoot 298 but I feel the performance will be better with the heavier arrow with the same KE and more MO to shoot expandables.

In running scenarios a 350 grain would actually increase ke to 61 but I have already dropped enough on arrows to call it day for 1 lb of KE
 
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