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Anonymous
Anonymous asked in SportsOutdoor RecreationHunting · 1 month ago

how much kinetic energy am i getting from this crossbow? ?

i do not have a chronograph. 

it is a 10" powerstroke, 125 lb crossbow with a 400 grain arrow. 

what is the FPS? what is the FPE? 

2 Answers

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  • BBean
    Lv 7
    1 month ago

    I agree with Adam D...you`re SOL (Shjt Outta Luck...to explain the acronym) without an accurate measurement of speed. But, my curiosity is not satisfied. I have plenty of experience with bows including making them from a bois d`arc stave after spending hours just trying to come up with a good stave and then working it before it went from hard to near impossible. Yes, I know, you`re talking about a cross bow...not a long bow. I made a couple of them also but out of leaf springs from a Crosley car. 

    Point being is that I never had a need to know the kinetic energy in all those years...still do not. Just wondering why the need today? You have the pull rated at 125 pounds and the arrow at 400 grains so I would like to know myself just for coffee shop conversation.

    However, even after impressing someone with boundless knowledge....how could I prove it necessary to know? 

    I do not want to appear as Ahole but if my curiosity nagged me long enough I would buy a chronograph. A question that comes to mind

    is....would the length of an arrow(bolt) passing through a chronograph vs the length of a bullet have any effect on the reading? 

    There are a lot of guys that have come and gone from this section that would know but there`s one left that could answer that question to my satisfaction. Just maybe.

    FYI; You should at least mention once the full meaning of your acronyms. Did you know there are over 30 things FPE could stand for?

    FPS is easily assumed because it relates to the subject matter.

  • Adam D
    Lv 7
    1 month ago

    Without knowing how fast the bolt is going, there's no way to calculate kinetic energy.  So without a chronograph, you're SOL.  If you knew the speed, you could Google a calculator that would spit out an answer without you needing to understand anything about how it worked.

    You might be able to use the advertised speed for the crossbow and take them for their word, though that number is always optimistic.

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