When trying to determine FOC% what is the formula you use. My arrows are 30" from nock to tip and my balance point is 2 inches in front of center.
FOC AMO Standard Formula
% FOC= (( Dist. Knock throat to balance point ) - 0.50) X 100 /
(( Shaft Length )
* Shaft Length – bottom of nock's throat to end of shaft excluding insert and point (BH)
Normal FOC – >0% to 12%
High FOC - >12% to 19%
Extreme FOC - >19% to 29.9%
Ultra-EFOC - 30%+
http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=2;t=000089
I simply use the 3Rivers version of the Stu Miller Dynamic Spine Calculator...that will get me close enough for my purposes...the truth is adequate FOC is not difficult to achieve
DDave
For a long time I measured FOC the way Friend says to do it and didn't worry about it. But then I started using VAP's that have about 1 1/2" of outsert sticking out the end of the shaft before you get to the point. I wonder if that should be ignored? Does anyone know why we don't measure the whole arrow length, including the point, rather than excluding the point and adapter?
McDave, point lengths can vary a lot, measuring to end of shaft standardizes it. Look at the VPA 3 blade and 2 blade, length can differ by .5" or more.
I think I would measure to the end of outsert.