Arrow speed

Discussion in 'General Archery Forum' started by [email protected], Jun 16, 2009.

  1. How do I make my chrono graph display a higher number? I'm sure there is an adjustment screw in there somewhere I could turn clock wise (or counter clockwise) and adjust it until I reach my desired arrow speed.

    I am thinking a modest 15 - 20 fps increase in displayed speed will be enough to keep me from worrying about my arrow being too slow

    It's ironic that we (I) dump as much money as we (I) do into these bows with tuning, arrow set ups etc, only to shoot it through the chronograph and get relatively dismal results.

    I am confidant in one of two possible truths here.
    1. My chronograph is off by as much as 5% (10 - 20fps)

    2. Everyone is lying about the speed of their arrows.

    While Im sure there is some truth in #2, I myself have even been guilty of stretching things a bit. I seriously think my chrono is a lemon.

    Here is the most recent example of why I think that:

    I just picked up a lightly used bow on Sunday.

    The bow is a beautiful Elite XXL.

    It came with its birth certificate.

    On the birth certificate. The bow @ 29" and 61 pounds shot a 300 grain arrow at 311 fps.

    Looking at the IBO, of ~330fps - @ 29" the bow is rated at 306 - 316 - deduct 4 fps for 60# limbs - adjusted speed range should be 302 - 312

    that 311 is right smack in that specified range

    Now the fella I bought the bow off of said he put 30" modules in on account of he is a knuckle dragger like me. He said the bow chronos at 322 with a 5gpp arrow.

    Looking at the conversion from 29" to 30" on Elites supplied chart - IBO = 317 - 327 - deduct the same 4 fps for 60 pound limbs = 313 - 323

    Perfectly linear adjustment. Very predictable.

    So I got the bow home and put several arrows through my 97 dollar pro chrono with Light attachment.

    295!! That is almost a 30 fps variance.

    So I need to know where the speed adjustment is on my chronograph.
    Thanks in advance :)
     
  2. JAVI

    JAVI New Member

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    Where in the world did you get that 10lbs of draw weight equaled 4 fps...:noidea: It's more like 2 fps per pound...
     
    Last edited: Jun 16, 2009

  3. That came off of the supplied chart from Elite for this bow.

    "Deduct 4 fps for 60 pound limbs - Deduct 8 fps for 50 pound limbs"

    the 5gpp arrow being consistent that seems plausible.
     
  4. Looney Bin

    Looney Bin Guest

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    Could you chrony be off?? It sure could. Go to a shop and shoot through their chrony. You would at least have some thing to compare it to. Secondly don't be surprised if that BC is a little fudged. I talked to a shop owner that sells Elite. He said he tested them out of the box through multiple Chrony's. His results were close to the BC but never as high. Do you have a peep and loop on the string??? Or anything else for that matter???
     
  5. Shot with just a D loop

    I am completely confidant that the advertised IBO speed is generous.

    Was referring more to the 311fps on the birth certificate and the claimed 322 from the nice and honest looking guy I bought it from.

    These pro chronos (Cabelas) have to have an adjustment screw somewhere...
     
  6. Looney Bin

    Looney Bin Guest

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    Did you tune this yourself??? Have you checked all the specs???? Are the strings new???