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Ok been using my chronograph again this year. Shooting my custom turned brass inserts weighted CE Surge 492gr arrows speed checks 345fps (130 KE). Shooting Dragon Claw (BE) and Gander TECHUNTER (Victory) both at 425grs am getting 360fps (122 KE).
Is this loss of KE efficiency normal on a recurve Xbow. Or are heavier bolts just more efficient?
BTW this is my Xbow below
 

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Speed X Mass = Force or KE in this case. People debate speed vs weight constantly in the arrow world. IMO there is a fine line I try to walk. I don't want too heavy/slow of an arrow, but I want enough weight/speed that it will still maintain some "punch" on the live target. But to answer your question to the best of my knowledge, the heavier arrow is likely more efficient in technical terms due to FOC. So in your set up's you are losing 15 FPS and 8 FT Lbs. of KE. That's not a terrible difference considering 67 grains between the two arrows. I would see how they both shoot at distance, then I would check the FOC of each set up and go from there as to which I would choose to use. All things being equal in terms of accuracy, and if the trajectory of the heavier set up isn't too crazy at distance, I would probably opt for the heavier of the two. This is just my opinion and I am by no means a XB Guru. I'm sure other's will chime in and give their perspective too. (y)
 

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15 fps is practically nothing and those two KE's will punch thru the ribcages of any deer in America. More just a personal thing I believe. My preference would be go with the faster flatter shooting arrow.;)
 
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Time to untangle the terminology a little. Force= mass*acceleration (not speed). Kinetic Energy= 1/2 mass*velocity^2 using Standard International Units. To express the answer in foot-pounds(F) starting with grain weight and fps, divide by 225218. If you don't take 1/2 the arrow weight to begin with, then you must divide by 450436. Brass inserts in the heavier arrow will give it an edge in FOC, but I would consider momentum loss in the lighter arrow (>9%) more important than KE loss (~6%). For hogs, black bear, elk, and moose and other slow-movers, I'd stick with the heavy arrow and use the 360 fps for white-tails and pronghorns.
 

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Time to untangle the terminology a little. Force= mass*acceleration (not speed). Kinetic Energy= 1/2 mass*velocity^2 using Standard International Units. To express the answer in foot-pounds(F) starting with grain weight and fps, divide by 225218. If you don't take 1/2 the arrow weight to begin with, then you must divide by 450436. Brass inserts in the heavier arrow will give it an edge in FOC, but I would consider momentum loss in the lighter arrow (>9%) more important than KE loss (~6%). For hogs, black bear, elk, and moose and other slow-movers, I'd stick with the heavy arrow and use the 360 fps for white-tails and pronghorns.

HUH??? LMAO! Yeah, whatever you just said GJ! :eek:
 
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