This is my first post! Been hiding in this tree for awhile (not too long,..cold out here!..lol) I haven't seen this info. here nor could I find out else where. Sorry if its a repeat. Now!,..that said. I keep seeing bows advertized with 308fps I.B.O. or 315fps I.B.O.. How does this compair to what your bows REALLY shooting? How do you calculate to get these numbers? Is this why you should try out a couple of different arrow set ups. i.e., broadhead weight, type., arrow weight, fletching? I wasn't checking for speed when I was shooting all those different arrows and set ups just looking for the most accutate, did I miss something? I'm not a fan of speed and I don't shoot 3-D, but I am curious about these numbers for no other reason than, just because???! I hunt deer and turkey and I don't think they really care either! Any and all input, ideas and yeah, jokes too, are welcome on this. Thanks!!
DMorg, the only way to compare an IBO rating to what your bows really shooting is to tell us what bow, poundage, draw length, arrow weight or type, etc.... The actual speed could be anywhere from near or over the IBO rating (for 3D shooters with over 30" draw lengths) to 100 fps less with a shorter draw length and heavy arrows. It appears to me that for hunting with a newer bow around 60 lbs, with average 28" or 29" DL, and mid weight arrows in the 400 grain range, people are shooting around around 250 - 280 fps. An older bow or heavier arrows maybe in the 220 - 230 range.
Are you asking how they actually come up with IBO speeds for bows. Well, here's a little article from Hunter's Friend. Read the article and it will answer any of your questions.
The actual article about IBO is a little ways down the page, but the whole article might help you even more.
Thanks for the replys. The Huntersfriend site was exspecially helpful Double edge!! As for my bow, its nothing fancy Blodg, Its a PSE NOVA set at 66lbs, a 29 1/2 inch draw length, 62% let off. I'm shooting Carbon Force 400 arrows with a 125 grain fixed broadhead. (Steel Force) It seems to scoot along pretty good but I'm fairly certain its not shooting the posted 295 f.p.s. IBO speed, But, I've never shot through a chronograph. So..?? I was always interested in how the manufactuers came up with these numbers and I appreciate the help. I have thought about shooting 100grain heads but other than that I really like my set up and it seems to work well, as long as I do all I need to. Thanks again for the help!!!
As an example, my Reflex Grizzly set at 27" Draw length with a 340 gr arrow and 64 lbs draw weight shoots 257 fps. The IBO rating for that bow is 305 FPS. So deduct the 3" DL, the 6lbs Draw weight, the tube peep, the string leeches etc.... and I am pretty darn close to what it is advertised with all the deductions factored in.
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I don't like people who don't like dogs !
IBO is extremely misleading to those bowhunters who don't know all the ends and outs of the archery world. MOST IBO speeds are given using 70lbs, 30 inch draw lengths and 350 grain arrows. Personally, I think AMO is a better guide to go by for bowhunters.
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" If he smells you its over. If he gets in your wind stream its over, If he smells where you walked, he probably aint coming back... Your talking about an animal that can smell a fingerprint. Any amount over 0% is to much." Dan Infalt
I.B.O. speed or Actual speed
