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Is there a web site that you can accurately calculate the foc for the carbon express arrows with the built in forward weight

There are several, Back Country Bowhunting is one! I think!! Why not do them yourself, very easy.
1) measure arrow from tip to tip with ft or bh on
2) divide that total length by 2
3) find center of shaft and subtract from # in line 2
4) multiple that number by 100
5) take that number and divideit by arrows total length

To change a fraction to a decimal, divide the lower number into upper number! Rember the weight is forward, the more you take off the front the less foc you will have.

http://www.odproshops.com/foccalculator.htm

Try this.