Arrow spine question

Discussion in 'Tech Talk' started by JLhunts, Nov 1, 2016.

  1. JLhunts

    JLhunts Weekend Warrior

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    The arrows are easton axis 400s. So a 27" arrow with a 50grain brass insert and 100 grain broadhead, finished weight would be about 430 and pretty high FOC. Theyll be shot out of a bear effect 27" draw and 65lbs. Ive shot the same setup without the extra 50grains up front so will this extra weight weaken the spine? Should i go with a heavier spine?
     
    Last edited: Nov 1, 2016
  2. bow nut

    bow nut Weekend Warrior

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    Yes, fixed blades if that's what you shoot, won't impact the same
     
  3. b_fitnik

    b_fitnik Weekend Warrior

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    I have similar specs. 27.5" draw, 27" arrow, 26gr insert with 30gr insert weight(56gr total), 100gr, field point, 65lb draw. Not sure of your ibo but mine is 338fps. I shoot the 350 spine and they shoot and tune very well. I'm no professional but responded since our specs are so similar


    Sent from my iPhone using Tapatalk
     
  4. JLhunts

    JLhunts Weekend Warrior

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    Yea im in a 400 spine with my specs but just that extra weight up front. Be a waste to make them arrows with the insert and have then fly like crap. Thanks for the info guys
     
  5. BB4tw

    BB4tw Die Hard Bowhunter

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    Most spine charts are made with standard inserts and 100 grain tips used for the calculations.

    If you add weight up front then you need to read the chart at least one block to the left. Another way to think about it would be to read your arrow length column one inch longer than what you actually have.

    Charts and other people's setups are only rough starting points though. Trial and error is the true test to find out what you really need/like.
     
  6. JLhunts

    JLhunts Weekend Warrior

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    I get what your saying but a half dozen arrows is an expensive "trial and error" test. Unless im mistaken if i make these arrows this way they will be stuck like that and pretty useless to me if theyre under spined.
     
  7. Coop

    Coop Grizzled Veteran

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    I think a 400 is going to be weak with 50 grns added to the front at 65lbs even at 27". You could cut them a little shorter than 27" since your draw is 27" and that will stiffen them some. Most people like to err on the side of stiff spine vs weak spine though. So if you want to keep them 27" I say go to the next stiffer spine choice. Just my opinion of course.
     
  8. trial153

    trial153 Grizzled Veteran

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    Your boarder line. If your getting a too weak reaction out of them just turn your bow down a couple pounds and call it a day. Honestly 60 vs 65 pounds isn't going to make a spit of difference however a well tuned bow/arrow combination will.
     
  9. JLhunts

    JLhunts Weekend Warrior

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    I do have a couple old beman hunters in a 400 spine i could sacrifice to try out that setup. Thats a good idea too trial its a 70# bow and i only got it out maybe a turn so ill try backin it out if i get some spine issues.
     
  10. Arkyinks

    Arkyinks Weekend Warrior

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    My thinking is your spine will be a bit weak. Look at bare shaft tuning instead of just chopping the shafts off to some standard measurement. With carbon shafts an inch can make a world of difference.
     

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