Check out this image....



Let's take my arrows as an example:

Beman ICS Hunter 340's (regular stockarrows,right out of the box)
Cut length: 29.25" ("TAL" in the image above)
Balance point: 17.8125" ("APB" in the image above)
Field tips/broadheads: 100 grain

(17.8125 / 29.25) - .50 X 100 === 10.89% FOC

Arrow FOC as per OnTarget2 software: 10.68 %

I got very close to OT2's figure, as I went a little extreme, and used a piece of fishing line tied around the arrow and found the balance point, that way.

Butch A.