Couple of points:

- IBO the group has NOTHING to do with IBO speed ratings. Its named that because IBO 3D rules state 5 gr/lb arrow weight. IBO the group has nothing to do with it and is NOT a certifying body, nor is it an industry standard. AMO speed (540 gr arrow at 60 lb, 30 inches) IS an industry standard, but results in a MUCH lower speed so isn't as "cool" looking as IBO spped. Your "real" speed will be somewhere between em probably.

- the IBO speed is VERY hard to achieve. Everything you do to a bow to make it shootable slows it down, anything on the string, peep, loop, nock point etc, slow it down.

- 350 gr arrow at 70 lbs is pretty tough to do without going underspined and very tough to do with a broadhead due to BH weights.

Use the IBO rating as a comparison only. If one bow is IBO rated at 315 and another at 295 you can tell which will be faster, but don' t be suprised if you don't get that number.

My bow is IBO rated at 305, I shoot it at 30 inches (IBO does to), 65 lbs (5 under IBO) and 400 grain arrow (50 over IBO), with a loop and peep sight. I get 270 fps.

--Bob