friend is having problems getting broadheads to fly straight and consistantly. I've been helping tune. bow has a 22 strand 452x string, hoyt trykon, 70 lbs, 28" draw. Beman ICS 400 arrows at 27.5". Technically according to the chart, its ok, but I'm suspecting a weak spine condition.

I'm still kind of new with the whole OT2 thing but I gave it a shot. I still don't understand the difference (on the program) when you check if the arrow is "target" or "hunting". Hunting arrows always show to be a bit more weak. but no spec seems to change.

Anyway, with a 100 grain tip...that would make him be a little underspined. Drop the weight down to 66-67 and its perfect.

thats about what I expected. Told him to back it off 2 turns each limb bolt and to give it a try.

Oh yeh, underspined. And I didn't need a computer program to figure it out. Easy way to find out is to take two turns off the limbs and see if they fly better.

Take one turn off the limbs or enough to get it down to 67 lbs. with 100 grain heads and it put you in the middle of the green zone. Two turns would put you a little ways into the overspined side.