Bobco, I've always liked to be up around 12-13% FOC with my broadheads. I think guys with l-o-n-g arrows need a pretty healthy FOC.
You know how I've been hollering about carbons not shooting well for me with broadheads? There has been kinda a run on FOC questions in the last day or so and it got me curious. I've done a little playing around with Jackson's FOC calculator. A 100 grain broadhead on my 32", 4" vane fletched Beman ICSH 340 gives me an FOC of 8.8%. Even a 125 gives me only 10.8%!! A 125 grainer on my 2315's with 5" feathers runs an FOC of 11.4%.
I couldn't believe it. So, I measured my arrows and, by golly, the numbers came out nearly dead on. I get higher FOC on a heavier arrow with 5" feathers than I do with a lighter arrow and 4" vanes. I know feathers are lighter than vanes but, really....
Like I said, I was shooting broadheads pretty good with 29" carbons off my overdraw and it all went down the tubes when I got rid of the OD and started shooting 32-inchers. It looks like my problem with carbon might be FOC just as much as it is straightness. Maybe more! Believe it or not, I've never really checked my FOC with carbon before, and it does make me feel awful stupid to have just noticed this. I should know better.<img src=icon_smile_dissapprove.gif border=0 align=middle>
I'm going to go do some experimenting.