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Thread: Can anyone explain what IBO and AMO means?

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  1. #1
    String builder/ Super Moderator Hutch~n~Son Archery's Avatar
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    Gilmanton, New Hampshire
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    Default Can anyone explain what IBO and AMO means?

    Can anyone explain what IBO and AMO means?

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  2. #2

    Default Can anyone explain what IBO and AMO means?

    That you put in AMO you are pointing to standards of fps once used by bow manufacturers. They don't use either.... Well, you can get AMO, but have to call the factory.

    So more or less for speed shooters;
    IBO is basically the rule set forth by the IBO, International Bowhunters Organization. Okay, 30" of draw, 70 pounds of draw weight and a arrow weighing 350 grs (5 grs per pound of draw weight).

    More or less heavy bowhunter equipment;
    AMO was formerly the Archery Manufacturers Association and now the Archery Trade Association. Here, the draw length is 30" with draw weight of 60 pounds and a 540 gr arrow.

    Today the IBO has been replaced and is confusing. Now called, ATA.
    ATA fps is to be derived from real numbers. Okay, IBO pounds could be that of up to 82 pounds so long as 5 grs. per pound of draw weight was used.
    Read link and I'll see what else I can find.
    Last edited by SonnyThomas; 01-28-2011 at 06:21 AM.

  3. #3
    Senior Member Ehunter's Avatar
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    Southeast Kansas
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    IBO is what bows wish they could shoot, and AMO is closer to what they will shoot. lol Or you could use Sonny's explanation. lol

  4. #4
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    exactly ehunter, ibo is for manufacture sales not real life hunting cause once you start rigging out your bow thats when it gets real, not what somebody selling a bow says your bow should shoot. hope im not stepping on toes.::

  5. #5

    Default Can anyone explain what IBO and AMO means?

    Manufacturer numbers are real, but we have to think of them as a starting point, not the finished bow set up. I would say these IBO and AMO listings are a starting point. Where would you start being there are some 3 1/2 million archers with whatever different number of bow setups?

    Again, I thought the ATA fps listing is confusing. As long as you have 5 grs of arrow weight per pound of draw weight what's the problem? Noted in the link was 82 pounds. So what? I mean, there are factory bow of 80 pound draw weight. Hoyt and others offer 80 pound bows! I know for a fact you can get bows of 100 pounds of draw weight.

    If you read the replies of the link you would have read of one person relating of REAL numbers. Well, more people do use a draw weight in the 60 pound range. Next real, real is the average male in the United States. He stands close to 5 foot 10 inches tall - so 70 inches tall which is normally that person's wing span. So 70 - 15 = 55 / 2 = 27 1/2" draw length.

    I have a Pearson TX4 with IBO rating of 340 fps. As is it has a 28" draw and maxed out at 62 pounds. I have a loop on the string and nothing else. I used a 314 gr arrow - so 4 grs heavier than allowed IBO spec. It chronograph-ed 310 fps.
    Using the below rule of thumb for speed adjustment I came up with the following;
    310 + 16 (dw) + 1 + (arrow weight) + 20 (dl) = 347 fps.

    And somewhere in here I did the same correction for my Shadowcat and came up with 323 fps. Listed is 320 to 325 fps.

    Rule of thumb for speed adjustment;
    2 fps / 1 # of Draw Weight
    10 fps / 1" of Draw Length
    1 fps / 3 grains of arrow weight
    1 fps / 3 grains of weight on the string

  6. #6

    Default Can anyone explain what IBO and AMO means?

    ??? Hutch, no comment?

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