Quote:
Originally Posted by brendan's dad
Doesn't Mathews do something a little different when calculating IBO that may result in a less than accurate comparison to the normal industry standards? Maybe just a rumor and I never took the time to verify my Z7, but I recall something I read on archery talk with Mathews using an 80lb bow for testing.... Maybe just a rumor.
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All bow manufacturers were obligated under IBO ratings if using IBO standards which are as follows...
And for the OP ..your MR 7 according to Mathews was 344 IBO
*How fast is your bow…Take rated IBO…
IBO speeds are based on a bow with a 30" draw set at 70lbs shooting a 350gr arrow.
-For every inch of draw length you go down you will lose 10 FPS
-For every 5# draw weight you go down you will lose 10 FPS
-For every 3 grains of weight your arrow is over IBO ( 5 grains per pound) you will lose 1 FPS
-For every 3 grains of weight you add to your string you will lose 1 FPS
so you can calculate approx speeds...
Having said that many bow manufacturers will push the 70 lb rule...use arrow with no vanes...on string with only wrapped nock point nothing else ...use mecanical shooter...all which exagerate speeds
Steps are in place such as with the ATA rating instead of IBO for realistic ratings....
Neil