i am new to archery and was wondering if there was a general amount of ibo speed you would subtract from the advertised ibo once you shoot with a hunting set up. (sorry that is a wordy question) for example if a bow's marked for 300 ibo how fast you it be shooting with a hunting set up(rest, sights, ect) assuming that the draw weight and length were at ibo standards (30 inches @70 pounds)
It has a lot more to do with your arrow weight. If your arrow is still at 5 grains per pound of draw weight, then your going to be pretty close assuming the manufacturer has accurate speed claims. Many manufacturers do not though. Typically the only things that will slow you down (other than heavier arrows, and innacurate speed claims) are the peep sight, loop, and nock points. These will typically slow you down anywhere from 5-12fps.
is that 5-12 per item? if i use a heavy arrow, peep sight, kisser botton how much would you subtract assuming factory ibo is somewhat correct
No way to guess without knowing the exact weight of your arrow, measured draw length, and exact draw weight. Plan on losing 5-12fps for just the peep/loop/nock points (combined).
there are some sites where you can plug in your arrow stuff and bow poundage and draw length and peep, kisser, etc....it will get you close...I will look for it.
As Matt said, it's just too highly variable since we all prefer different gear for hunting. The big difference is going to be from the weight of the arrow you shoot.
I shoot a 480 grain arrow at 60 pounds and 27 inch draw (29 inch shaft). The bow was advertised at 318 IBO fps and I get 240 actual. I also have a peep with tube and kisser button with Sims string leeches. It hits with authority.
I am not an expert by an stretch, but a decent estimation is 10fps for every inch of draw length under 30, 1-1.5 fps per pound draw weight, 1 fps per 5-6 grains of arrow above 5 grains per pound of draw weight, and then the 10 or so fps for nock/peep/etc. If you do the math on konrad's setup you get 318 - 10*(30-27) - 1*(70-60) - (1/6)*(480-300) - 10 = 238, which is pretty dang close to what he said he gets. At least it will get you in the ball park.
